Testament Beast

The is the creature resulting of the fusion of Schwarz and his group, through the use of Rosebank's Chaos Staff, so they help her and her allies defeat the Four Knights of the Apocalypse.

Appearance
The Testament Beast is a humanoid being of gigantic height with certain features similar to the demons that make it up. It has long arms and legs, a mop of long hair, two tails with stingers, and a face on its torso.

Personality
As a being controlled by the Chaos Staff, the Testament Beast acts like a savage monster without the use of reason. However, it is shown that retains a part of Schwarz's consciousness.

Demon Realm arc
Upon being created, the Testament Beast attacks and overwhelms Tristan until it is shot down by Chion and Isolde's Combined Technique: Keiken naru Inori. Then, he attacks Anghalhad with his poisonous tail, avoiding the girl's magic as it does not understand her language.

Tristan continues to face the monster but is unable to defeat it until Gawain joins him. The two are capable of fighting equally but the Testament Beast remains impossible for them to overcome. Then, upon seeing the monster's attack collide with Tristan's Falling Star, Gawain deduces that if Tristan combines his light magic with his dark magic, the force of both canceling each other will break his defenses, something only a Nephilim can do. Thus, Tristan uses his Annihilation technique, leaving the Testament Beast almost destroyed. However, the monster decides to use his remaining strength to destroy the entrance to Camelot, but Tristan manages to avoid this by reflecting its attack with Full Counter.

After receiving the reflected attack, the Testament Beast divides again into the demons that made it up.

Abilities and Equipment
The Testament Beast can breathe fire from the mouth on its chest. Their tails have poison that can incapacitate an enemy with a simple wound.