Once per turn, during your Main Phase, if you control this monster on the field, you can equip it to your “Dark Blade” as an Equip Spell Card OR change it back to a monster in face-up Attack Position. When equipped to a monster by this card’s effect, that

Once per turn, during your Main Phase, if you control this monster on the field, you can equip it to your "Dark Blade" as an Equip Spell Card, OR change it back to a monster in face-up Attack Position. When equipped to a monster by this card's effect, that monsters ATK/DEF is increased by 400 points, and when it attacks with an ATK that is higher than the DEF of a Defense Position monster, inflict the difference as Battle Damage to your opponent's Life Points. (1 monster can only be equipped with 1 Union Monster at a time. If the monster this card is equipped to is destroyed in battle, this card is destroyed instead.)