diff --git a/projects/mtg/include/AllAbilities.h b/projects/mtg/include/AllAbilities.h
index 335040493..bf811e464 100644
--- a/projects/mtg/include/AllAbilities.h
+++ b/projects/mtg/include/AllAbilities.h
@@ -3857,7 +3857,7 @@ public:
         MTGAbility(id, _source)
     {
         counters = 0;
-        int _cost[] = { Constants::MTG_COLOR_ARTIFACT, 4 };
+        int8_t _cost[] = { Constants::MTG_COLOR_ARTIFACT, 4 };
         cost = ManaCost(_cost, 1);
     }
 
@@ -3921,7 +3921,7 @@ public:
         MTGAbility(_id, _source)
     {
         canprevent = 0;
-        int _cost[] = { Constants::MTG_COLOR_ARTIFACT, 2 };
+        int8_t _cost[] = { Constants::MTG_COLOR_ARTIFACT, 2 };
         cost = ManaCost(_cost, 1);
     }
 
@@ -4017,7 +4017,7 @@ public:
     AFarmstead(int _id, MTGCardInstance * source, MTGCardInstance * _target) :
         ActivatedAbility(_id, source, 0, 1)
     {
-        int _cost[] = { Constants::MTG_COLOR_WHITE, 2 };
+        int8_t _cost[] = { Constants::MTG_COLOR_WHITE, 2 };
         cost = NEW ManaCost(_cost, 1);
         target = _target;
         usedThisTurn = 0;
diff --git a/projects/mtg/include/ManaCost.h b/projects/mtg/include/ManaCost.h
index 56ce2eb55..dab5b59a8 100644
--- a/projects/mtg/include/ManaCost.h
+++ b/projects/mtg/include/ManaCost.h
@@ -23,7 +23,7 @@ class ManaCost
     friend std::ostream& operator<<(std::ostream& out, ManaCost m);
 
 protected:
-    int cost[Constants::MTG_NB_COLORS+1];
+    int8_t cost[Constants::MTG_NB_COLORS+1];
     std::vector<ManaCostHybrid> hybrids;
 
 
@@ -55,7 +55,7 @@ public:
     virtual void reinit();
     void x();
     int hasX();
-    ManaCost(int _cost[], int nb_elems = 1);
+    ManaCost(int8_t _cost[], int nb_elems = 1);
     ManaCost();
     ~ManaCost();
     ManaCost(ManaCost * _manaCost);
@@ -82,8 +82,8 @@ public:
     int doPayExtra();
 
     int addHybrid(int c1, int v1, int c2, int v2);
-    int tryToPayHybrids(std::vector<ManaCostHybrid>& _hybrids, int _nbhybrids, int diff[]);
-    void randomDiffHybrids(ManaCost * _cost, int diff[]);
+    int tryToPayHybrids(std::vector<ManaCostHybrid>& _hybrids, int _nbhybrids, int8_t diff[]);
+    void randomDiffHybrids(ManaCost * _cost, int8_t diff[]);
     int add(ManaCost * _cost);
     int remove(ManaCost * _cost);
     int removeAll(int color);
diff --git a/projects/mtg/src/AIMomirPlayer.cpp b/projects/mtg/src/AIMomirPlayer.cpp
index b59aef232..11b851566 100644
--- a/projects/mtg/src/AIMomirPlayer.cpp
+++ b/projects/mtg/src/AIMomirPlayer.cpp
@@ -53,7 +53,7 @@ int AIMomirPlayer::momir()
 
     if (efficiency >= chance)
     {
-        int _cost[] = { Constants::MTG_COLOR_ARTIFACT, converted };
+        int8_t _cost[] = { Constants::MTG_COLOR_ARTIFACT, converted };
         ManaCost * cost = NEW ManaCost(_cost);
         MTGAbility * ability = getMomirAbility();
         MTGCardInstance * card = game->hand->cards[0];
diff --git a/projects/mtg/src/MTGAbility.cpp b/projects/mtg/src/MTGAbility.cpp
index a0ffe18d4..90747a9b5 100644
--- a/projects/mtg/src/MTGAbility.cpp
+++ b/projects/mtg/src/MTGAbility.cpp
@@ -2710,7 +2710,7 @@ void AbilityFactory::addAbilities(int _id, Spell * spell)
 
     case 1103: //Crystal Rod
     {
-        int cost[] = { Constants::MTG_COLOR_ARTIFACT, 1 };
+        int8_t cost[] = { Constants::MTG_COLOR_ARTIFACT, 1 };
         ASpellCastLife* ability = NEW ASpellCastLife(_id, card, Constants::MTG_COLOR_BLUE, NEW ManaCost(cost, 1), 1);
         game->addObserver(ability);
         break;
@@ -2742,7 +2742,7 @@ void AbilityFactory::addAbilities(int _id, Spell * spell)
     }
     case 1113: //Iron Star
     {
-        int cost[] = { Constants::MTG_COLOR_ARTIFACT, 1 };
+        int8_t cost[] = { Constants::MTG_COLOR_ARTIFACT, 1 };
         ASpellCastLife* ability = NEW ASpellCastLife(_id, card, Constants::MTG_COLOR_RED, NEW ManaCost(cost, 1), 1);
         game->addObserver(ability);
         break;
@@ -2754,7 +2754,7 @@ void AbilityFactory::addAbilities(int _id, Spell * spell)
     }
     case 1114: //Ivory cup
     {
-        int cost[] = { Constants::MTG_COLOR_ARTIFACT, 1 };
+        int8_t cost[] = { Constants::MTG_COLOR_ARTIFACT, 1 };
         ASpellCastLife* ability = NEW ASpellCastLife(_id, card, Constants::MTG_COLOR_WHITE, NEW ManaCost(cost, 1), 1);
         game->addObserver(ability);
         break;
@@ -2827,7 +2827,7 @@ void AbilityFactory::addAbilities(int _id, Spell * spell)
 
     case 1140: //Throne of Bone
     {
-        int cost[] = { Constants::MTG_COLOR_ARTIFACT, 1 };
+        int8_t cost[] = { Constants::MTG_COLOR_ARTIFACT, 1 };
         ASpellCastLife* ability = NEW ASpellCastLife(_id, card, Constants::MTG_COLOR_BLACK, NEW ManaCost(cost, 1), 1);
         game->addObserver(ability);
         break;
@@ -2835,7 +2835,7 @@ void AbilityFactory::addAbilities(int _id, Spell * spell)
 
     case 1142: //Wooden Sphere
     {
-        int cost[] = { Constants::MTG_COLOR_ARTIFACT, 1 };
+        int8_t cost[] = { Constants::MTG_COLOR_ARTIFACT, 1 };
         ASpellCastLife* ability = NEW ASpellCastLife(_id, card, Constants::MTG_COLOR_GREEN, NEW ManaCost(cost, 1), 1);
         game->addObserver(ability);
         break;
diff --git a/projects/mtg/src/ManaCost.cpp b/projects/mtg/src/ManaCost.cpp
index 29a263284..b1521cff7 100644
--- a/projects/mtg/src/ManaCost.cpp
+++ b/projects/mtg/src/ManaCost.cpp
@@ -243,7 +243,7 @@ ManaCost::ManaCost()
     init();
 }
 
-ManaCost::ManaCost(int _cost[], int nb_elems)
+ManaCost::ManaCost(int8_t _cost[], int nb_elems)
 {
     init();
     for (int i = 0; i < nb_elems; i++)
@@ -624,7 +624,7 @@ int ManaCost::isPositive()
 
 }
 
-void ManaCost::randomDiffHybrids(ManaCost * _cost, int diff[])
+void ManaCost::randomDiffHybrids(ManaCost * _cost, int8_t diff[])
 {
     for (size_t i = 0; i < _cost->hybrids.size(); i++)
     {
@@ -636,7 +636,7 @@ void ManaCost::randomDiffHybrids(ManaCost * _cost, int diff[])
 /**
     starting from the end of the array (diff) 
 */
-int ManaCost::tryToPayHybrids(std::vector<ManaCostHybrid>& _hybrids, int _nbhybrids, int diff[])
+int ManaCost::tryToPayHybrids(std::vector<ManaCostHybrid>& _hybrids, int _nbhybrids, int8_t diff[])
 {
     if (!_nbhybrids)
         return 1;
@@ -664,7 +664,7 @@ int ManaCost::tryToPayHybrids(std::vector<ManaCostHybrid>& _hybrids, int _nbhybr
 //compute the difference between two mana costs
 ManaCost * ManaCost::Diff(ManaCost * _cost)
 {
-    int diff[(Constants::MTG_NB_COLORS + 1) * 2];
+    int8_t diff[(Constants::MTG_NB_COLORS + 1) * 2];
     diff[Constants::MTG_NB_COLORS * 2] = Constants::MTG_NB_COLORS;
     for (int i = 0; i < Constants::MTG_NB_COLORS; i++)
     {