ATK increases depending on the number of empty slots on equipment.
[Y = 0] [Unknown Condition] [Y = Y + 1] [Unknown Condition] [Y = Y + 1] [Unknown Condition] [Y = Y + 1] [Unknown Condition] [Y = Y + 1] [Unknown Condition] [Y = Y + 1] [Unknown Condition] [Y = Y + 1] [Unknown Condition] [Y = Y + 1] [Unknown Condition] [Y = Y + 1] [Y = Y · 10] [ATK up by Y]