Abyss Demon

Abyss Demon (深淵の悪魔) is a demon summon from Mass for the Dead.

Appearance
A muscular demon with the bare-bone head of a ram with black wings sprouting from the back.

Personality
Abyss Demon possesses the intelligence to speak human language and strength to crush rocks. He combines obedience that faithfully carries out its life in the service of Demiurge and Momonga. Ferocious in that, if he considers those as an enemy, he will crush them without mercy. Abyss Demon may look like a thug, but he has a prudent mind and can sense an enemy's power. He is not without his insecurities, as after surviving a near-death experience from fighting Blue Roses, he became agitated and fearful of their faces. To nurse his damaged psyche he has continuously told himself, and others, that he was invincible.

Background
One of the subordinates summoned by Demiurge during the Great Tomb of Nazarick's crisis.

Mass for the Dead Arc
Abyss Demon appears alongside his superior Demiurge on the 6th Floor after sweeping through wiping out the Chaos Beasts. He listened to the Floor Guardian's theory concerning the fissures on the 6th and 10th Floors and the possibility that they were connected. It was his summoner's belief that the randomness of the Chaos Beasts' attacks were part of some intelligent design. Abyss Demon was shocked at such a possibility that there was someone out there that could possess such power. Though he was relieved of his worries by Demiurge that all this was just pure speculation.

In order to obtain resources to promote and revitalize Nazarick, Momonga launches an asset acquisition plan. However, the mine for resource acquisition secured by Demiurge, become threaten when word is received that a teams of adventurers led by Blue Roses is coming. Abyss Demon aids Demiurge in turning the mind into a dungeon. The theme for the dungeon is decided as a place for demons, and Abyss Demon is installed as the nominal boss. While the minions placed by the demons kill the weak adventurers, they fail to stop Blue Roses. Abyss Demon is forced to confront them as the lord of the dungeon.

Demiurge using his abilities from afar, temporarily increases Abyss Demon's defensive stats to make him seemingly invulnerable. In the end, he allows a killing blow to hit him and is defeated by Lakyus Alvein Dale Aindra's weapon, Kilineiram using [Dark Blade Mega Impact]. The demon is severely injured and near defeat, but before the adventurers land a killing blow, agents from Nazarick, working undercover as adventurers, secretly activate poison gas that emits seemingly from Abyss Demon's body. The adventurers quickly evacuate the mine, whilst Abyss Demon is rescued and taken to Nazarick to be resuscitated by Demiurge. After being healed by his summoner, he is traumatized by the experience at the hands of the humans. Though he was defeated, the mission was a success as the mine is now indefinitely free from human interference.

Eventually a quake occurred in the vicinity of the hidden mine, revealing several untouched underground caverns filled with precious ores. This new area was surveyed and explored by Demiurge, Solution Epsilon, Sebas Tian, Slimeko, the protagonist. After the survey, the Abyss Demon was granted to rule the area, nominally promoting him as an Area Guardian, an honor that he took with pride.

Abyss Demon continued to work under the service of Demiurge, often acquiring human material for the Floor Guardian's projects. For instance he abducted two bandits and gave them to Demiurge to be used to breed more Enhanced Treants for Nazarick's security network.

On one of his routine duties in clearing away random monsters from his dungeon, he was assisted by Shalltear Bloodfallen. Everything went accordingly until Shalltear received a [Message] from Solution Epsilon of Albedo plan to seduce Momonga. In fury the Floor Guardian rushed out of the mine, leaving behind the confused demon.

For the protagonist's upcoming mission to rescue Gazef Stronoff, Abyss Demon met with the homunculus and his adventurer team and escorted them to the Crack in the Great Forest of Tob for training.

Abyss Demons is later seen as part of the demon forces of the Demon Emperor Jaldabaoth. While the Evil Lords actively participated in the campaign to exterminate thirty thousand Chaos Beasts, Abyss Demon was kept in reserve to intimidate the observing humans. His presence does not go unnoticed by Lakyus who suspects he was revived by Jaldabaoth.

The Abyss Demon finally took an active part in Jaldabaoth's scheme when the protagonist, who was really Pandora's Actor in disguise, interfered with the execution of Jircniv Rune Farlord El-Nix in city square of E-Rantel. Abyss Demon was ordered by Jaldabaoth to eliminate the adventurer, but was quickly defeated despite his bluster on being invincible.

Much later after his defeat, Abyss Demon was suspected by the Blue Roses to be behind the rise in undead in a mine near Re-Blumrushur. Together with the protagonist's team they found that the mine was being used as a ritual site by Zurrernorn and they believed he was the mastermind. However the mastermind of the death cult's presence was seemingly to be Evil Lord Greed who fought the adventurers on behalf of his traumatized comrade.

After Demiurge returned from the Abelion Hills with ore of adamantite from a newly discovered mine, Abyss Demon went to meet meet Demiurge on the 7th Floor to talk about planes for the mine's management. There he found Demiurge with Evil Lord Envy and Evil Lord Greed having an artistic block on how to proceed with making a statue of Momonga. Demiurge asked Abyss Demon on his opinion on one sample of his work, which the demon found to be beautiful, but was shocked to learn it was merely one of 83 prototypes. However Abyss Demon could not provide anything constructive as he lack a truly artistic eye, which caused the Floor Guardian to call Albedo for her opinion. When Albedo arrived and reviewed Demiurge's progress she was able to give him some insight on his block and also inspire him to resume. Abyss Demon observed in stunned awe at his superior and the Overseer Guardians dynamic in creating the final iteration of the statue. Later at the National Foundation Day Ceremony, Abyss Demon attended the event and stood among the subordinates in the Throne Room of Fake Nazarick.

Abilities and Powers
Abyss Demon belongs to the sub-type of demonic beings known as devils, ones who are the intellectuals of the race.

Active

 * Abyss: Inflicts physical damage on a single enemy.
 * Angel Killing: Increases damage a single enemy of the "Angel" species.
 * Body Strengthening: Increases physical attack power.
 * Duplicate Slash: An attack that gives the damage to a single enemy.

Main Equipment

 * Halberd

Demiurge
Abyss Demon's summoner, and due to that he is loyal to him. He also listens to his summoner's theories on the origins of the Cracks. While he does not understand the hypothetical questions regarding the phenomena, he also shares Demiurge's wariness of that the Cracks could be a form of attack by some unseen mastermind.

Momonga
Momonga being Demiurge's master is also loyal to him.

Trivia

 * Abyss Demon is the second summoned character in Mass for the Dead.