It has inherent Sap status, which was supposed to restore HP due to it being undead, but due to a glitch it slowly saps its HP every turn. Its major threat is Gravity, which it uses frequently to cut the HP of a party member in half. Angel Whispers like to attack in packs. Sabin's Rising Phoenix is an effective strategy for dealing with them. Otherwise, normal physical attacks should be enough. Angel Whisper has an attack, Impmare, that was meant to inflict Imp, but it never uses the attack, making it a dummied feature.