The Drain ability is found in Search Ghost's Enemy Card; it drains the enemy's HP for every attack cards used, but using the ability will decrease items drop rate. Sora can obtain the Search Ghost Enemy card and then use the ability anytime, whereas Riku automatically obtains the card upon entering Monstro, however he can only use it there.
Kingdom Hearts Birth by Sleep
The Drain ability is used as Maleficent's Dimension Link's secondary effect. It drains enemy's HP for every type of attack used.
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