Forum:B.E.S Crystal Core

Okay so this card has 3 counters and can't be destroyed by battle. When he battles a monster he loses a counter,and when he can no longer remove a counter he is destroyed. So say he battles with a monster 3 times and and now he has 0 counters. Is he immediately destroyed when he has 0 counters or do you wait till he battles another monster and THEN he is destroyed cause he can't remove another counter?