Trick Weapon

As a bonus action, you can switch between the transformed and untransformed states of this weapon by sliding the pommel up and down on the blade. In its untransformed state, the abyss warden's axeblade is a longsword. In its transformed state, the weapon becomes a battleaxe. As part of this bonus action, you can slam the weapon down, emitting
a wave of radiance centered on you. Each creature within 5 feet of you must succeed on a DC 15 Constitution saving throw or take 1d8 radiant damage.