Moss

Moss (モス) is an archduke in the underworld and one of Testarossa's subordinates. He has stood undefeated for tens of thousand of years, with his strength second only to the Primordials. Along with Cien, he serves as Testarossa's lieutenant.

Appearance
He assumes the appearance of an adorable young boy who, according to Rimuru, looks like an elementary school student in 5th or 6th grade. His ash-grey hair, an offshoot of Testarossa's signature silver white, is proof of his lineage. From appearances alone he doesn't come off as formidable at all, even though he's a super old demon whose lived several millennia.

Personality
He usually holds a calm and levelheaded disposition in contrast with his appearance, and is fairly intelligent. In the presence of his superiors, Moss gets super timid to the point his own presence in the room thins out. He is very loyal -- attending to Testarossa for several millennia in spite of her personality is proof of that -- and he shows extreme humbleness whenever praised. He's quick to rage when his master is insulted in any manner and will proceed to ruthlessly kill the offender unless it goes against his orders.

Background
A Demon of the pre-historic species and a high ranking figure of the ruling class in the Demon world; he is a subordinate of Blanc. In the past, he often dueled the lieutenant serving under Violet several times and always emerged the victor, cursing the latter to the fate of repeated reincarnations. One day he gets recruited by Diablo along with his master to serve Rimuru. Initially he was opposed to Diablo's demands (as with several others), but after taking a beating from him he reluctantly bended to his coercion in the end. Upon meeting Rimuru and acquiring a body, he and Blanc receive the names "Moss" and "Testarossa", respectively. They both evolve to Demon Peers. From then onwards they genuinely pledge their loyalties to Rimuru, both settle in Tempest as their HQ. Moss specializes in reconnaissance and espionage, similar to Souei. He's also an officer in the Black Numbers reporting directly to Diablo, with Testarossa holding a superior position as a co-leader. He frequently escorts Testarossa as her aide in her new post as Military Attaché. undefined

Relationships
Testarossa: He's highly devoted to her. In fact, it's an accomplishment that he even stood by her side for as long as he has despite her egocentric personality, a testament to his loyalty. Moss does not tolerate any insult towards her. He's very quick to amend his conduct when pissing her off.

Rimuru Tempest: He gave him both a name and body. Moss admires his wisdom and foresight and like all of Rimuru's subordinates, does not tolerate disrespect towards him.

Diablo: His boss and superior. After folding to his coercion, Moss now serves as his officer in the Black Numbers.

Souei: They work together per Rimuru's recommendation, their similar talents and capabilities complement each other well enough that they cooperate from time to time.

Veyron: They've dueled several times in the Underworld and now operate in Tempest together as fellow Officers of the Black Numbers.

Cien: A fellow lieutenant of Testarossa. They serve as Officers of the Black Numbers.

Trivia

 * Named after the, a limited edition of the Mercedes-Benz SLR McLaren, which is in turn refurbishing of the 50s' Mercedes-Benz 300 SLR.
 * After the Primordials, Moss is the next strongest Demon.