diff --git a/composeApp/src/commonMain/composeResources/values/strings.xml b/composeApp/src/commonMain/composeResources/values/strings.xml
index 2af9d3a..2027681 100644
--- a/composeApp/src/commonMain/composeResources/values/strings.xml
+++ b/composeApp/src/commonMain/composeResources/values/strings.xml
@@ -318,6 +318,7 @@
     <string name="game_master__item__edit_stackable">Empilable</string>
     <string name="game_master__item__edit_equipable">Équipable</string>
     <string name="game_master__item__edit_consumable">Consommable</string>
+    <string name="game_master__item__edit_add_alteration">Ajouter une alteration</string>
     <string name="game_master__character_edit__title">Édition de personnage</string>
 
 </resources>
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/common/tag/GMTag.kt b/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/common/tag/GMTag.kt
index ac47243..c195595 100644
--- a/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/common/tag/GMTag.kt
+++ b/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/common/tag/GMTag.kt
@@ -12,6 +12,7 @@ import androidx.compose.material.MaterialTheme
 import androidx.compose.material.Surface
 import androidx.compose.material.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Immutable
 import androidx.compose.runtime.Stable
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Shape
@@ -30,8 +31,9 @@ data class GMTagUio(
     val meta: Boolean,
 )
 
-@Stable
+@Immutable
 object GmTagDefault {
+    @Stable
     val padding = PaddingValues(horizontal = 8.dp, vertical = 4.dp)
 }
 
@@ -83,11 +85,16 @@ fun GMTag(
     }
 }
 
+@Immutable
+object GmTagButtonDefault {
+    @Stable
+    val padding = PaddingValues()
+}
 
 @Composable
 fun GMTagButton(
     modifier: Modifier = Modifier,
-    padding: PaddingValues = GmTagDefault.padding,
+    padding: PaddingValues = GmTagButtonDefault.padding,
     shape: Shape = MaterialTheme.shapes.small,
     tag: GMTagUio,
     onTag: (() -> Unit)? = null,
diff --git a/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMAlterationFieldItemUio.kt b/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMAlterationFieldItemUio.kt
new file mode 100644
index 0000000..ade2211
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMAlterationFieldItemUio.kt
@@ -0,0 +1,222 @@
+package com.pixelized.desktop.lwa.ui.screen.gamemaster.item.edit
+
+import androidx.compose.animation.AnimatedContent
+import androidx.compose.animation.SizeTransform
+import androidx.compose.animation.animateContentSize
+import androidx.compose.animation.core.animateFloatAsState
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.slideInVertically
+import androidx.compose.animation.slideOutVertically
+import androidx.compose.animation.togetherWith
+import androidx.compose.foundation.background
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.heightIn
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.material.DropdownMenuItem
+import androidx.compose.material.ExperimentalMaterialApi
+import androidx.compose.material.ExposedDropdownMenuBox
+import androidx.compose.material.Icon
+import androidx.compose.material.IconButton
+import androidx.compose.material.MaterialTheme
+import androidx.compose.material.Text
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.ArrowDropDown
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Immutable
+import androidx.compose.runtime.Stable
+import androidx.compose.runtime.State
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import com.pixelized.desktop.lwa.ui.theme.lwa
+import com.pixelized.desktop.lwa.utils.extention.calculateHorizontalPaddings
+import com.pixelized.desktop.lwa.utils.extention.ribbon
+import kotlinx.coroutines.flow.StateFlow
+
+@Stable
+data class GMAlterationFieldItemUio(
+    val key: String,
+    val value: StateFlow<Field?>,
+    val error: StateFlow<String?>,
+    val menu: List<Field>,
+) {
+    @Stable
+    data class Field(
+        val id: String,
+        val label: String,
+    )
+}
+
+@Immutable
+data object AlterationFieldItemDefault {
+    @Stable
+    val padding = PaddingValues(horizontal = 16.dp, vertical = 8.dp)
+
+    @Stable
+    val spacing = 8.dp
+}
+
+@Composable
+fun GMAlterationFieldItem(
+    modifier: Modifier = Modifier,
+    padding: PaddingValues = AlterationFieldItemDefault.padding,
+    spacing: Dp = AlterationFieldItemDefault.spacing,
+    field: GMAlterationFieldItemUio,
+    onAlteration: (GMAlterationFieldItemUio.Field?) -> Unit,
+    onRemoveField: (String) -> Unit,
+) {
+    val error = field.error.collectAsState()
+    val menu = remember { mutableStateOf(false) }
+
+    AlterationFieldContent(
+        modifier = modifier,
+        padding = padding,
+        spacing = spacing,
+        isOpen = menu,
+        isError = error,
+        field = field,
+        onOpenStateChange = { menu.value = it },
+        onAlteration = {
+            menu.value = false
+            onAlteration(it)
+        },
+        onRemoveField = onRemoveField,
+    )
+}
+
+@Composable
+@OptIn(ExperimentalMaterialApi::class)
+fun AlterationFieldContent(
+    modifier: Modifier = Modifier,
+    padding: PaddingValues,
+    spacing: Dp,
+    isOpen: State<Boolean>,
+    isError: State<String?>,
+    field: GMAlterationFieldItemUio,
+    onOpenStateChange: (Boolean) -> Unit,
+    onAlteration: (GMAlterationFieldItemUio.Field?) -> Unit,
+    onRemoveField: (String) -> Unit,
+) {
+    val horizontal = padding.calculateHorizontalPaddings()
+
+    Column(
+        modifier = Modifier
+            .animateContentSize()
+            .then(other = modifier),
+    ) {
+        Row(
+            horizontalArrangement = Arrangement.spacedBy(space = spacing),
+        ) {
+            ExposedDropdownMenuBox(
+                modifier = Modifier
+                    .weight(weight = 1f)
+                    .clip(
+                        shape = MaterialTheme.shapes.small,
+                    )
+                    .background(
+                        color = MaterialTheme.lwa.colorScheme.elevated.base1dp,
+                    )
+                    .ribbon(
+                        color = when (isError.value) {
+                            null -> Color.Transparent
+                            else -> MaterialTheme.lwa.colorScheme.base.error
+                        }
+                    ),
+                expanded = isOpen.value,
+                onExpandedChange = onOpenStateChange,
+            ) {
+                Row(
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .height(height = 48.dp)
+                        .padding(paddingValues = horizontal),
+                    verticalAlignment = Alignment.CenterVertically,
+                ) {
+                    AnimatedContent(
+                        modifier = Modifier.weight(1f),
+                        targetState = field.value.value?.label,
+                        transitionSpec = {
+                            val enter = fadeIn()
+                            val exit = fadeOut()
+                            enter togetherWith exit using SizeTransform(clip = false)
+                        },
+                    ) {
+                        Text(
+                            style = MaterialTheme.typography.body1,
+                            overflow = TextOverflow.Ellipsis,
+                            maxLines = 1,
+                            text = it ?: "",
+                        )
+                    }
+                    val rotation = animateFloatAsState(
+                        targetValue = if (isOpen.value) -180f else 0f,
+                    )
+                    Icon(
+                        modifier = Modifier.graphicsLayer { rotationZ = rotation.value },
+                        imageVector = Icons.Default.ArrowDropDown,
+                        contentDescription = null
+                    )
+                }
+                ExposedDropdownMenu(
+                    modifier = Modifier.heightIn(max = 480.dp),
+                    expanded = isOpen.value,
+                    onDismissRequest = { onOpenStateChange(false) }
+                ) {
+                    field.menu.forEach {
+                        DropdownMenuItem(
+                            onClick = { onAlteration(it) },
+                            enabled = true,
+                            interactionSource = remember { MutableInteractionSource() },
+                            content = {
+                                Text(
+                                    color = MaterialTheme.colors.primary,
+                                    text = it.label,
+                                )
+                            },
+                        )
+                    }
+                }
+            }
+
+            IconButton(
+                modifier = Modifier
+                    .size(size = 48.dp)
+                    .background(
+                        color = MaterialTheme.lwa.colorScheme.elevated.base1dp,
+                        shape = MaterialTheme.shapes.small,
+                    ),
+                onClick = { onRemoveField(field.key) },
+            ) {
+                Icon(
+                    imageVector = Icons.Default.Close,
+                    tint = MaterialTheme.lwa.colorScheme.base.primary,
+                    contentDescription = null,
+                )
+            }
+        }
+        isError.value?.let {
+            Text(
+                style = MaterialTheme.typography.caption,
+                color = MaterialTheme.colors.error,
+                text = it
+            )
+        }
+    }
+}
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMItemEditFactory.kt b/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMItemEditFactory.kt
index cb08b20..0aeeb8f 100644
--- a/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMItemEditFactory.kt
+++ b/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMItemEditFactory.kt
@@ -4,9 +4,16 @@ import com.pixelized.desktop.lwa.ui.composable.checkbox.LwaCheckBoxUio
 import com.pixelized.desktop.lwa.ui.composable.textfield.createLwaTextField
 import com.pixelized.desktop.lwa.ui.composable.textfield.createLwaTextFieldFlow
 import com.pixelized.desktop.lwa.ui.screen.gamemaster.common.tag.GMTagFactory
+import com.pixelized.shared.lwa.model.alteration.Alteration
 import com.pixelized.shared.lwa.model.item.Item
 import com.pixelized.shared.lwa.model.tag.Tag
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.mapNotNull
+import kotlinx.coroutines.flow.stateIn
 import lwacharactersheet.composeapp.generated.resources.Res
 import lwacharactersheet.composeapp.generated.resources.game_master__item__edit_description
 import lwacharactersheet.composeapp.generated.resources.game_master__item__edit_id
@@ -14,6 +21,7 @@ import lwacharactersheet.composeapp.generated.resources.game_master__item__edit_
 import lwacharactersheet.composeapp.generated.resources.game_master__item__edit_label
 import lwacharactersheet.composeapp.generated.resources.game_master__item__edit_thumbnail
 import org.jetbrains.compose.resources.getString
+import java.util.UUID
 
 class GMItemEditFactory(
     private val tagFactory: GMTagFactory,
@@ -21,6 +29,7 @@ class GMItemEditFactory(
     suspend fun createForm(
         item: Item?,
         tags: Collection<Tag>,
+        alterationFlow: StateFlow<Map<String, Alteration>>,
     ): GMItemEditViewModel.GMItemEditForm {
         val idFlow = createLwaTextFieldFlow(
             label = getString(Res.string.game_master__item__edit_id),
@@ -51,6 +60,17 @@ class GMItemEditFactory(
                 selectedTagIds = item?.tags ?: emptyList(),
             )
         )
+        val alterations = MutableStateFlow(
+            item?.alterations
+                ?.associate { alterationId ->
+                    val field = GMItemEditViewModel.GMItemEditForm.GMAlterationFieldItemFlow(
+                        errorFlow = MutableStateFlow(null),
+                        valueFlow = MutableStateFlow(alterationId)
+                    )
+                    field.key to field
+                }
+                ?: emptyMap()
+        )
         return GMItemEditViewModel.GMItemEditForm(
             idFlow = idFlow,
             labelFlow = labelFlow,
@@ -61,12 +81,15 @@ class GMItemEditFactory(
             equipableFlow = equipableFlow,
             consumableFlow = consumableFlow,
             tagFlow = tagFlow,
+            alterationsFlow = alterations,
         )
     }
 
-    fun createForm(
-        form: GMItemEditViewModel.GMItemEditForm,
+    fun createPage(
+        scope: CoroutineScope,
         originId: String?,
+        alterations: Map<String, Alteration>,
+        form: GMItemEditViewModel.GMItemEditForm,
     ): GMItemEditPageUio {
         return GMItemEditPageUio(
             id = form.idFlow.createLwaTextField(enable = originId == null),
@@ -86,31 +109,82 @@ class GMItemEditFactory(
                 checked = form.consumableFlow,
                 onCheckedChange = { form.consumableFlow.value = it },
             ),
+            alterations = form.alterationsFlow.map { data ->
+                data.map { entry ->
+                    createAlterationUio(
+                        key = entry.key,
+                        value = entry.value.valueFlow.mapNotNull { alterationId ->
+                            if (alterationId == null) return@mapNotNull null
+                            val alteration = alterations[alterationId] ?: return@mapNotNull null
+                            GMAlterationFieldItemUio.Field(
+                                id = alterationId,
+                                label = alteration.metadata.name,
+                            )
+                        }.stateIn(
+                            scope = scope,
+                            started = SharingStarted.Eagerly,
+                            initialValue = null,
+                        ),
+                        error = entry.value.errorFlow,
+                        alterations = alterations.values,
+                    )
+                }
+            }.stateIn(
+                scope = scope,
+                started = SharingStarted.Eagerly,
+                initialValue = emptyList(),
+            ),
             tags = form.tagFlow,
         )
     }
 
     fun createItem(
-        form: GMItemEditPageUio?,
+        form: GMItemEditViewModel.GMItemEditForm?,
     ): Item? {
         if (form == null) return null
         return Item(
-            id = form.id.valueFlow.value,
+            id = form.idFlow.valueFlow.value,
             metadata = Item.MetaData(
-                label = form.label.valueFlow.value,
-                description = form.description.valueFlow.value,
-                image = form.image.valueFlow.value,
-                thumbnail = form.thumbnail.valueFlow.value,
+                label = form.labelFlow.valueFlow.value,
+                description = form.descriptionFlow.valueFlow.value,
+                image = form.imageFlow.valueFlow.value,
+                thumbnail = form.thumbnailFlow.valueFlow.value,
             ),
             options = Item.Options(
-                stackable = form.stackable.checked.value,
-                equipable = form.equipable.checked.value,
-                consumable = form.consumable.checked.value,
+                stackable = form.stackableFlow.value,
+                equipable = form.equipableFlow.value,
+                consumable = form.consumableFlow.value,
             ),
-            tags = form.tags.value
+            tags = form.tagFlow.value
                 .filter { it.highlight }
                 .map { it.id },
-            alterations = emptyList(), // TODO,
+            alterations = form.alterationsFlow.value.values
+                .mapNotNull { it.valueFlow.value },
+        )
+    }
+
+    fun createAlterationUio(
+        key: String,
+        value: StateFlow<GMAlterationFieldItemUio.Field?>,
+        error: StateFlow<String?>,
+        alterations: Collection<Alteration>,
+    ): GMAlterationFieldItemUio {
+        return GMAlterationFieldItemUio(
+            key = key,
+            value = value,
+            error = error,
+            menu = alterations.map { alteration ->
+                createAlterationFieldUio(alteration)
+            },
+        )
+    }
+
+    private fun createAlterationFieldUio(
+        alteration: Alteration,
+    ): GMAlterationFieldItemUio.Field {
+        return GMAlterationFieldItemUio.Field(
+            id = alteration.id,
+            label = alteration.metadata.name,
         )
     }
 }
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMItemEditPage.kt b/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMItemEditPage.kt
index fe6478e..0f21988 100644
--- a/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMItemEditPage.kt
+++ b/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMItemEditPage.kt
@@ -15,8 +15,6 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.calculateEndPadding
-import androidx.compose.foundation.layout.calculateStartPadding
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
@@ -37,11 +35,11 @@ import androidx.compose.material.TextButton
 import androidx.compose.material.TopAppBar
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material.icons.filled.Add
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.Stable
 import androidx.compose.runtime.State
 import androidx.compose.runtime.collectAsState
-import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
@@ -49,7 +47,7 @@ import androidx.compose.ui.input.key.Key
 import androidx.compose.ui.input.key.KeyEventType
 import androidx.compose.ui.input.key.key
 import androidx.compose.ui.input.key.type
-import androidx.compose.ui.platform.LocalLayoutDirection
+import androidx.compose.ui.platform.LocalFocusManager
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import androidx.navigation.NavHostController
@@ -65,15 +63,19 @@ import com.pixelized.desktop.lwa.ui.screen.gamemaster.common.tag.GMTagButton
 import com.pixelized.desktop.lwa.ui.screen.gamemaster.common.tag.GMTagUio
 import com.pixelized.desktop.lwa.ui.theme.color.component.LwaButtonColors
 import com.pixelized.desktop.lwa.ui.theme.lwa
+import com.pixelized.desktop.lwa.utils.extention.calculateHorizontalPaddings
+import com.pixelized.desktop.lwa.utils.extention.calculateVerticalPaddings
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.launch
 import lwacharactersheet.composeapp.generated.resources.Res
 import lwacharactersheet.composeapp.generated.resources.game_master__action__save
 import lwacharactersheet.composeapp.generated.resources.game_master__item__create
+import lwacharactersheet.composeapp.generated.resources.game_master__item__edit_add_alteration
+import lwacharactersheet.composeapp.generated.resources.game_master__item__edit_consumable
 import lwacharactersheet.composeapp.generated.resources.game_master__item__edit_equipable
 import lwacharactersheet.composeapp.generated.resources.game_master__item__edit_stackable
-import lwacharactersheet.composeapp.generated.resources.game_master__item__edit_consumable
 import lwacharactersheet.composeapp.generated.resources.ic_save_24dp
 import org.jetbrains.compose.resources.painterResource
 import org.jetbrains.compose.resources.stringResource
@@ -89,6 +91,7 @@ data class GMItemEditPageUio(
     val stackable: LwaCheckBoxUio,
     val equipable: LwaCheckBoxUio,
     val consumable: LwaCheckBoxUio,
+    val alterations: StateFlow<List<GMAlterationFieldItemUio>>,
     val tags: MutableStateFlow<List<GMTagUio>>,
 )
 
@@ -102,6 +105,7 @@ fun GMItemEditPage(
     viewModel: GMItemEditViewModel = koinViewModel(),
 ) {
     val screen = LocalScreenController.current
+    val focus = LocalFocusManager.current
     val scope = rememberCoroutineScope()
 
     val form = viewModel.form.collectAsState()
@@ -110,16 +114,34 @@ fun GMItemEditPage(
         modifier = Modifier.fillMaxSize(),
         form = form,
         onBack = {
+            focus.clearFocus(force = true)
             screen.navigateBack()
         },
         onSave = {
+            focus.clearFocus(force = true)
             scope.launch {
                 if (viewModel.save()) {
                     screen.navigateBack()
                 }
             }
         },
+        onAddAlteration = {
+            focus.clearFocus(force = true)
+            viewModel.addAlteration()
+        },
+        onAlteration = { field, selected ->
+            focus.clearFocus(force = true)
+            viewModel.toggleAlteration(
+                field = field,
+                selected = selected,
+            )
+        },
+        onRemoveAlteration = {
+            focus.clearFocus(force = true)
+            viewModel.removeAlteration(key = it)
+        },
         onTag = { tag ->
+            focus.clearFocus(force = true)
             viewModel.addTag(tag = tag)
         },
     )
@@ -144,21 +166,13 @@ private fun GMItemEditContent(
     paddings: PaddingValues = GMItemEditDefault.paddings,
     onBack: () -> Unit,
     onSave: () -> Unit,
+    onAddAlteration: () -> Unit,
+    onAlteration: (GMAlterationFieldItemUio, GMAlterationFieldItemUio.Field?) -> Unit,
+    onRemoveAlteration: (String) -> Unit,
     onTag: (GMTagUio) -> Unit,
 ) {
-    val layoutDirection = LocalLayoutDirection.current
-    val verticalPadding = remember(paddings) {
-        PaddingValues(
-            top = paddings.calculateTopPadding(),
-            bottom = paddings.calculateBottomPadding(),
-        )
-    }
-    val horizontalPadding = remember(paddings, layoutDirection) {
-        PaddingValues(
-            start = paddings.calculateStartPadding(layoutDirection = layoutDirection),
-            end = paddings.calculateEndPadding(layoutDirection = layoutDirection),
-        )
-    }
+    val verticalPadding = paddings.calculateVerticalPaddings()
+    val horizontalPadding = paddings.calculateHorizontalPaddings()
 
     Scaffold(
         modifier = modifier,
@@ -216,6 +230,7 @@ private fun GMItemEditContent(
 
                     else -> {
                         val tags = it.tags.collectAsState()
+                        val alterations = it.alterations.collectAsState()
 
                         LazyColumn(
                             modifier = Modifier.fillMaxSize(),
@@ -351,6 +366,22 @@ private fun GMItemEditContent(
                                     }
                                 }
                             }
+                            items(
+                                items = alterations.value,
+                                key = { field -> field.key },
+                            ) { field ->
+                                GMAlterationFieldItem(
+                                    modifier = Modifier
+                                        .animateItem()
+                                        .fillMaxWidth()
+                                        .padding(paddingValues = horizontalPadding),
+                                    field = field,
+                                    onAlteration = { alterationId ->
+                                        onAlteration(field, alterationId)
+                                    },
+                                    onRemoveField = onRemoveAlteration,
+                                )
+                            }
                             item(key = "Actions") {
                                 Column(
                                     modifier = Modifier
@@ -359,6 +390,20 @@ private fun GMItemEditContent(
                                         .padding(paddingValues = horizontalPadding),
                                     horizontalAlignment = Alignment.End
                                 ) {
+                                    Button(
+                                        colors = LwaButtonColors(),
+                                        shape = CircleShape,
+                                        onClick = onAddAlteration,
+                                    ) {
+                                        Text(
+                                            modifier = Modifier.padding(end = 4.dp),
+                                            text = stringResource(Res.string.game_master__item__edit_add_alteration),
+                                        )
+                                        Icon(
+                                            imageVector = Icons.Default.Add,
+                                            contentDescription = null,
+                                        )
+                                    }
                                     Button(
                                         colors = LwaButtonColors(),
                                         shape = CircleShape,
diff --git a/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMItemEditViewModel.kt b/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMItemEditViewModel.kt
index e2ba1a3..f4621e1 100644
--- a/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMItemEditViewModel.kt
+++ b/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/ui/screen/gamemaster/item/edit/GMItemEditViewModel.kt
@@ -4,6 +4,7 @@ import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.pixelized.desktop.lwa.network.LwaNetworkException
+import com.pixelized.desktop.lwa.repository.alteration.AlterationRepository
 import com.pixelized.desktop.lwa.repository.item.ItemRepository
 import com.pixelized.desktop.lwa.repository.tag.TagRepository
 import com.pixelized.desktop.lwa.ui.composable.error.ErrorSnackUio
@@ -20,9 +21,11 @@ import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
+import java.util.UUID
 
 class GMItemEditViewModel(
     private val itemRepository: ItemRepository,
+    private val alterationRepository: AlterationRepository,
     private val tagRepository: TagRepository,
     private val factory: GMItemEditFactory,
     savedStateHandle: SavedStateHandle,
@@ -35,9 +38,11 @@ class GMItemEditViewModel(
     private val _form = MutableStateFlow<GMItemEditForm?>(null)
     val form: StateFlow<GMItemEditPageUio?> = _form.map {
         if (it == null) return@map null
-        factory.createForm(
-            form = it,
+        factory.createPage(
+            scope = viewModelScope,
             originId = argument.id,
+            form = it,
+            alterations = alterationRepository.alterationFlow.value
         )
     }.stateIn(
         scope = viewModelScope,
@@ -50,12 +55,15 @@ class GMItemEditViewModel(
             _form.value = factory.createForm(
                 item = itemRepository.item(itemId = argument.id),
                 tags = tagRepository.itemsTags(),
+                alterationFlow = alterationRepository.alterationFlow,
             )
         }
     }
 
     suspend fun save(): Boolean {
-        val edited = factory.createItem(form = form.value) ?: return false
+        if (!isFormValid()) return false
+
+        val edited = factory.createItem(form = _form.value) ?: return false
 
         try {
             itemRepository.updateItem(
@@ -77,6 +85,29 @@ class GMItemEditViewModel(
         }
     }
 
+    private suspend fun isFormValid(): Boolean {
+        var isValid = true
+
+        // check for empty values
+        _form.value?.alterationsFlow?.value?.values
+            ?.forEach { field ->
+                if (field.valueFlow.value.isNullOrBlank()) {
+                    field.errorFlow.value = "Empty alteration are not allowed."
+                    isValid = false
+                }
+            }
+
+        // check for duplicate alterations id.
+        _form.value?.alterationsFlow?.value?.values
+            ?.duplicates { it.valueFlow.value }
+            ?.forEach { field ->
+                field.errorFlow.value = "Duplicate alteration are not allowed."
+                isValid = false
+            }
+
+        return isValid
+    }
+
     fun addTag(tag: GMTagUio) {
         _form.value?.tagFlow?.update { tags ->
             tags.toMutableList().also {
@@ -88,6 +119,38 @@ class GMItemEditViewModel(
         }
     }
 
+    fun toggleAlteration(
+        field: GMAlterationFieldItemUio,
+        selected: GMAlterationFieldItemUio.Field?,
+    ) {
+        _form.value?.alterationsFlow?.update { alterations ->
+            alterations.toMutableMap().also {
+                it[field.key]?.valueFlow?.value = selected?.id
+                it[field.key]?.errorFlow?.value = null
+            }
+        }
+    }
+
+    fun addAlteration() {
+        _form.value?.alterationsFlow?.update { alterations ->
+            alterations.toMutableMap().also {
+                val flow = GMItemEditForm.GMAlterationFieldItemFlow(
+                    errorFlow = MutableStateFlow(null),
+                    valueFlow = MutableStateFlow(null),
+                )
+                it[flow.key] = flow
+            }
+        }
+    }
+
+    fun removeAlteration(key: String) {
+        _form.value?.alterationsFlow?.update { alterations ->
+            alterations.toMutableMap().also {
+                it.remove(key)
+            }
+        }
+    }
+
     data class GMItemEditForm(
         val idFlow: LwaTextFieldFlow,
         val labelFlow: LwaTextFieldFlow,
@@ -97,6 +160,23 @@ class GMItemEditViewModel(
         val stackableFlow: MutableStateFlow<Boolean>,
         val equipableFlow: MutableStateFlow<Boolean>,
         val consumableFlow: MutableStateFlow<Boolean>,
+        val alterationsFlow: MutableStateFlow<Map<String, GMAlterationFieldItemFlow>>,
         val tagFlow: MutableStateFlow<List<GMTagUio>>,
-    )
+    ) {
+        data class GMAlterationFieldItemFlow(
+            val key : String = "${UUID.randomUUID()}-${System.currentTimeMillis()}",
+            val errorFlow: MutableStateFlow<String?>,
+            val valueFlow: MutableStateFlow<String?>,
+        )
+    }
+
+    private inline fun <T, R> Iterable<T>.duplicates(selector: (T) -> R): List<T> {
+        val set = HashSet<R>()
+        val list = ArrayList<T>()
+        for (e in this) {
+            val key = selector(e)
+            if (!set.add(key)) list.add(e)
+        }
+        return list
+    }
 }
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/utils/extention/PaddingValues+calculatePaddings.kt b/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/utils/extention/PaddingValues+calculatePaddings.kt
index 09078f4..722a711 100644
--- a/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/utils/extention/PaddingValues+calculatePaddings.kt
+++ b/composeApp/src/commonMain/kotlin/com/pixelized/desktop/lwa/utils/extention/PaddingValues+calculatePaddings.kt
@@ -24,6 +24,27 @@ fun PaddingValues.calculatePaddings(
     )
 }
 
+@Composable
+@ReadOnlyComposable
+fun PaddingValues.calculateVerticalPaddings(): PaddingValues {
+    return PaddingValues(
+        top = calculateTopPadding(),
+        bottom = calculateBottomPadding(),
+    )
+}
+
+
+@Composable
+@ReadOnlyComposable
+fun PaddingValues.calculateHorizontalPaddings(
+    layoutDirection: LayoutDirection = LocalLayoutDirection.current,
+): PaddingValues {
+    return PaddingValues(
+        start = calculateStartPadding(layoutDirection = layoutDirection),
+        end = calculateEndPadding(layoutDirection = layoutDirection),
+    )
+}
+
 @Immutable
 @Stable
 data class ComputedPaddingValues(