Nightstar awakening really improved from Vampire. The problems with Nightstar is the damage output is a slow startup and he can't really attack below him. But he finally defines the characteristics of a vampire, such as health drain. To maximize his damage, kill 5 enemies in one shot with him. Make sure he keeps his distance from enemies that can knock him higher up in the air.
-Equip your Hero with Awakening Coffin Balalaika/El Diablo(覚醒:棺バラライカ/エルディアブロ)
-Equip a 2+ Vampire with Awakening Coffin Acacia/Mimosa (覚醒棺アカシア/ミモザ)
-Recovers 10% of his HP for each enemy killed
-Powers up in a 150%-200% increase (up to 1400% from 550%) for each enemy killed (papillon butterflies indicate powerup).