Zatch Bell! - S1E53

So Giaku, The Water Dragon of Rage!

A mamodo who's in love with Zatch comes to Kiyo's school in search of him. When she comes face to face with Zatch, he can't remember her. She swears that she will never forgive him and will burn his book. At Kiyo's school, she challenges Kiyo and Zatch to a battle.