- "So fleeting."
- "He's about to disappear."
- "He's see-through!"
- ― Iruma Suzuki, Asmodeus Alice and Clara Valac commenting on the fact that demon Ami Kirio looks like a ghost (Welcome to Demon School! Iruma-kun)
- Demonic-Undead Mimicry
- Necrodemon/Necrotic Demon Mimicry/Physiology
- Undead-Demon Mimicry/Physiology
- Undead-Demonic Mimicry/Physiology
- Undemon Mimicry/Physiology
A user with this ability either is or can transform into a combination of a demon and an undead. Their presence is extremely unnatural and/or corrupt. They specialize in the raw power of unholy and necrotic energies for powerfully destructive effects.
- Demon Physiology
- Malefic Force Manipulation
- Undead Physiology
- Undead Pulse
- Dark Lord
- Death-Force Manipulation
- Demonic-Alien Physiology
- Demon Sorcerer Physiology
- Hybrid Physiology
- Lich Physiology
- Mutated Demon Physiology
- Transcendent Hybrid Physiology
- Certain hybrid types may still rely on their undead species need to feed on blood, life-force, flesh, etc.
- May be vulnerable to holy powers, artifacts and incantations.
- If resurrected, may lose access to undead powers.
- May corrupt the user's mind.
- Might be weak to Purification.
For fan-fictional to non-canon characters, see here.