diff --git a/server/card/equipment/artifact/element_artifacts.py b/server/card/equipment/artifact/element_artifacts.py
index dafcbf76..9b0a1230 100644
--- a/server/card/equipment/artifact/element_artifacts.py
+++ b/server/card/equipment/artifact/element_artifacts.py
@@ -3,7 +3,9 @@
 from .base import ArtifactBase
 from ....struct import Cost
 from ....modifiable_values import CostValue
-from ....consts import ElementType, ObjectPositionType, CostLabels
+from ....consts import (
+    ELEMENT_TO_DIE_COLOR, ElementType, ObjectPositionType, CostLabels
+)
 from ....event import RoundPrepareEventArguments
 from ....action import Actions
 
@@ -117,16 +119,10 @@ def value_modifier_COST(
                             # talent card not for this charactor
                             return value
             # can decrease cost
-            used = 0
-            if (value.cost.elemental_dice_color == self.element
-                    and value.cost.elemental_dice_number > 0):
-                value.cost.elemental_dice_number -= 1
-                used += 1
-            elif value.cost.any_dice_number > 0:
-                value.cost.any_dice_number -= 1
-                used += 1
-            if mode == 'REAL':
-                self.usage -= used
+            if value.cost.decrease_cost(ELEMENT_TO_DIE_COLOR[self.element]):
+                # decrease cost success
+                if mode == 'REAL':
+                    self.usage -= 1
         return value
 
 
diff --git a/server/status/team_status/event_cards.py b/server/status/team_status/event_cards.py
index f0cb16ce..9cc308e3 100644
--- a/server/status/team_status/event_cards.py
+++ b/server/status/team_status/event_cards.py
@@ -37,13 +37,11 @@ def value_modifier_COST(
         if not (value.cost.label & CostLabels.SWITCH_CHARACTOR.value):
             # not switch charactor, do nothing
             return value
-        if value.cost.any_dice_number <= 0:
-            # no need dice, do nothing
-            return value
-        # self switch charactor, reduce cost by 1
-        value.cost.any_dice_number -= 1
-        if mode == 'REAL':
-            self.usage -= 1
+        # decrease 1 any cost
+        if value.cost.decrease_cost(None):
+            # decrease success
+            if mode == 'REAL':
+                self.usage -= 1
         return value
 
     def event_handler_SWITCH_CHARACTOR(
diff --git a/server/struct.py b/server/struct.py
index 9d1c4c87..e2e1b5a0 100644
--- a/server/struct.py
+++ b/server/struct.py
@@ -146,6 +146,39 @@ def total_dice_cost(self) -> int:
             + self.any_dice_number + self.omni_dice_number
         )
 
+    def decrease_cost(self, dice_color: DieColor | None) -> bool:
+        """
+        Decrease the cost by 1 dice of the given color in-place.
+
+        Return True if decrease successfully, False if not.
+
+        Args:
+            dice_color (DieColor | None): The dice color to be decreased.
+                If None, decrease same or any dice; Otherwise, decrease
+                elemental or any dice.
+        """
+        assert dice_color != DieColor.OMNI, 'Omni dice is not supported yet.'
+        if dice_color is None:
+            # decrease same or any dice
+            if self.same_dice_number > 0:
+                self.same_dice_number -= 1
+                return True
+            if self.any_dice_number > 0:
+                self.any_dice_number -= 1
+                return True
+            return False
+        # decrease elemental or any dice
+        if (
+            self.elemental_dice_color == dice_color
+            and self.elemental_dice_number > 0
+        ):
+            self.elemental_dice_number -= 1
+            return True
+        if self.any_dice_number > 0:
+            self.any_dice_number -= 1
+            return True
+        return False
+
     def is_valid(self, dice_colors: List[DieColor], charge: int, 
                  arcane_legend: bool, strict = True) -> bool:
         """