Regeneration...
Demons could heal their bodies using magic; however, it had its limits. Regenerating a hand was easy, but certain rules had to be followed. For instance, a hand would only regenerate if its absence was due to an accident or not caused by the hand's owner. This rule applied universally, as ancient demons sought to prevent abuse of their abilities by self-inflicted harm. Therefore, a hand severed by an enemy could be regenerated, but if someone intentionally cut their hand, there was nothing that could be done about it.
Moreover, only the most powerful healers could perform such feats.
She, on the other hand...
Diana lifted her gaze, forcing herself to look at Maximilian Knight. How could a vampire command her like this? No, vampires were naturally inferior to those who created them. Apart from strength, speed, and various weaker magic, they could not harm their creators in any way.