They are good, they are holy,... but only during working hours. In their free time, the Demi Angels reserve the right to misbehave, so if you see them somewhere angels should absolutely not be, just look the other way and keep walking.
Demi Angels have high Attack Speed, which becomes even fatter when their special phase is triggered, dealing an impressive number of hits to their target.
Because of this attack rate, they work very well close to units who can Electrocute and are a nightmare to single Melee enemies.
Bring them over to Ancient battles against Lava Lord! They’re a great counter to him.