I have booked and maxed "Keeyra The Watcher" for only one purpose, which is Decreasing the attack of the Clan Boss. He is very helpfull as weel to reduce the cooldown of the Increase Attack Debuff of the Clan Boss.

His passive is "Whenever an ally is attacked while under an [Ally Protection] buff, places a 50% [Decrease ATK] debuff on the attacker for 1 turn."

My question is does he place the Decrease Attack debuff before the clan boss hit or does he place it after the hit?