Doitsu (DR04-EN025) - Dark Revelation Volume 4 Unlimited

Once per turn, during your Main Phase, if you control this card on the field, you can equip it to your Soitsu as an Equip Card, OR unequip the Union equipment and Special Summon this card in face-up Attack Position. While equipped to a monster by this card''s effect, increase the ATK of the equipped monster by 2500 points. (1 monster can only be equipped with 1 Union Monster at a time. If the equipped monster is destroyed as a result of battle, destroy this card instead.)