Nicknamed the "Lord of Destruction" (破壊神, Hakaishin), he is the captain of the Black Bulls, considered the worst Magic Knight Squad, and recruits Asta.

Despite his aggression, he serves as a mentor to the Black Bulls, urging them to "surpass their limits" (Japanese: 限界をこえる, Hepburn: genkai wo koeru).

In June 2018, in an interview Yūki Tabata, the author of Black Clover, stated that Yami's creation was inspired by Toshiaki Iwashiro, who he had worked under as an assistant.

Yami then learns his father is planning a coup and offers him a drug that would draw out his latent power while in a bloodthirsty trance.

He was then recruited into the magic knight squad Gray Deer by future Wizard King Julius Novachrono, who taught Yami the country's language.

The priest of the temple Gifso makes the squad play a game to gain the stone, with Yami not allowed to participate.

[12] Six months after the magic knights ally with the Heart Kingdom against the Spade Kingdom, Dante of the Dark Triad comes to the Black Bulls' base to abduct Yami, whose dark magic is needed to form the Tree of Qliphoth to bring devils into the human world, fighting the Black Bulls there.

Unable to defeat Dante alone due to his body magic's regeneration, Yami acknowledges Asta and asks for his help.

Together, the two barely manage to defeat Dante, with Yami passing Asta his katana during the fight to land the final blow.

[13] During the Spade Kingdom Invasion, Yami is encased in a tomb alongside William Vengeance where they are being used to connect the underworld to the human world.

Asta ends up using Yami's sword to deliver a slash that cuts the manifestation open, finally freeing the captain.

Notable spells include Dark Coated Dimension Slash, which can bypass conventional durability by targeting space itself, and the Equinox variant, which does the same thing but with a substantially better range.

Additionally, Yami had learnt rudimentary Ki applications as an original inhabitant of his prior home country Land of the Sun in order to sense the life force of other living beings around him.

Demon soul pills in the past have never resulted in the user being able to stay sane and were thought to increase one's urge to kill.

[22] Daniel Dockery from Crunchyroll praised how Yami "was (and is) infinitely cool, a father figure whose approval means so much to his team.

"[23] Writing for Anime News Network, Rachel Trujillo mentioned Asta's mentorship relationship with Yami Sukehiro as a highlight of the series, saying "The defining moment of their relationship comes when Yami passes Asta his katana during their battle against Dante, which represents not only a culmination of their time spent together as mentor and student, but also the ultimate sign of trust from a captain to his subordinate.

"[25] Philip Van der Walt from Comic Watch called Yami "simultaneously one of the most badass and comedic characters in the series, and never misses the chance to inspire his team to keep improving and push past their limits.

"[26] Anjali Mehta spoke positively of Yami's comedic moments, bringing up his penchant for violence, tactlessness, and bullying of his squad.