[Technique]

April 8, 2003
Direct Damage spells in Player vs. Player combat can only do up to 75% damage of the target's maximum hit points in a single hit. This modification is done before resists are taken into account. For example, if a player has 1000 hit points when fully healed, no single direct damage spell will do more than 750 damage to him in a single hit.

http://www.tski.co.jp/baldio/patch/20030408.html