Demons and angels possess remarkable longevity, with lifespans extending well beyond 20,000 years. Unlike non-demons or non-angels, they can endure even after their HP drops to zero, which would typically be fatal. It has been stated that demons "do not die so easily," and they can even withstand having their beating hearts removed from their bodies. Furthermore, demons possess the ability to resurrect themselves by absorbing human consciousness, and can continue to revive as long as there is still human consciousness available to drain. Laharl has stated that demons are the embodiment and source of all things evil. It has been stated that demons, angels, and people who are dead do not require air, enabling them to survive in the vacuum of space. Demons can sense the presence of evil energy and curses. Laharl or anyone can use his Mana in order to create other demons. https://youtu.be/FnN5p13dDoM?t=339