TV-Series
Description
Nacht Faust is the vice-captain of the Black Bull squad of the Clover Kingdom's Magic Knights and a devil host who commands multiple devils through forbidden devil-binding rituals. He is a former nobleman of House Faust, a family that practiced forbidden magic. Nacht has fair skin, long black hair tied in a high ponytail, light blue eyes, and wears a plain cord necklace from which hang four devil-connected relics. He has a scar on his left wrist.

Nacht's past is defined by tragedy involving his twin brother Morgen. While Morgen joined the Magic Knights to protect people, Nacht indulged in his family's dark legacy. His arrogance during a ritual led to an incident that cost Morgen his life, an event that became the defining guilt of Nacht's existence. He dyed his hair and dedicated himself entirely to the mission Morgen left behind, effectively killing the version of himself his brother had loved.

Personality-wise, Nacht is cynical, detached, and openly critical of others, particularly those he considers reformed or redeemed. He believes that doing one good deed does not erase a lifetime of being a bad person, which creates tension within the Black Bulls, a squad built from societal rejects and former delinquents. He often criticizes Captain Yami Sukehiro's leadership style and initially dislikes the squad he leads. Despite this cold exterior, he is driven by a deep sense of guilt and a utilitarian philosophy that evil must be used to destroy evil. He is fiercely dedicated to protecting righteous people and carrying out the work his brother could not finish.

Nacht's role in the story is that of a shadow operator. For several years, he worked as a spy within the Spade Kingdom, gathering critical intelligence about the Dark Triad and their devil contracts. He rarely appears until the later arcs of the series, when his knowledge and abilities become pivotal. He becomes instrumental in training Asta to better control his devil powers and serves as a key fighter against high-ranking devils.

His key relationships include a complex history with Yami Sukehiro, whom he knew before joining the Magic Knights. Their relationship is marked by mutual respect and underlying tension, with Nacht often questioning Yami's methods while still working to protect the squad. He initially holds the other Black Bulls at a distance, viewing them as tools rather than comrades, but over time he grows to appreciate their bonds and abilities. By the end of major conflicts, he admits that the Black Bulls have surpassed his expectations.

Nacht undergoes significant character development. He starts as a guilt-ridden loner who believes he is beyond redemption and who views his devils as necessary evils rather than partners. Through his interactions with the Black Bulls, particularly Asta, he learns to value teamwork and trust. He proves that redemption can take the form of a long, lonely walk in the dark rather than a celebration, and that one does not have to be pure to do the right thing.

In terms of abilities, Nacht possesses Shadow Magic, which allows him to manipulate darkness for restraint, transportation, observation, and combat. He has immense mana as a former noble and is proficient in Mana Zone, enabling him to manipulate the magic surrounding him to enhance his spells. His most distinctive power is his contract with four mid-ranking devils: Gimodelo, Slotos, Plumede, and Walgner. Through relics linked to these devils, he can summon them in beast forms or merge with them in Unite Mode. Each devil grants unique enhancements: Canis mode provides shadow pack creatures; Equus mode grants great physical defense and resilience; Felis mode dramatically increases speed and agility; and Gallus mode enables stealth, reconnaissance, and shadow constructs that can emit disorienting sounds. Nacht can also combine modes, such as Gallus and Felis together, for more powerful effects. His Mana Zone technique, Dark Prison Hunting Ground, creates a zone of total darkness that deprives opponents of their senses. He relies on these relics, however, so damage to them severely weakens him. His stamina is exceptional, allowing him to engage top-tier devils even when badly injured, and his background as a spy makes him a strategic mastermind in battle.