Munetaka Yagyu is an older, dark and mysterious figure who appears in the latter half of the second season. He has an injured eye and a scar, dresses in Western-style clothing, carries a katana, and rides a motorcycle. His past is an enigma, but his evil powers were seen throughout Japan's history. He was once sealed away by earlier Stars of Fate, but later broke free and was reborn, continuing his quest for domination.

Yagyu works from the shadows and is the prime antagonist. His ultimate goal is to throw society into chaos and conflict, seeking a new world order to exalt himself. He is manipulative, using others as pawns to achieve his ends. Initially, he uses Marie Claire as his servant to observe the progress of Tendou Kodzunu, and the black cat that Claire keeps is his familiar. He granted Tendou Kodzunu and Renji Magatsu their demonic arcane abilities, though both were overcome by the Dark Arts and turned into demons. Later, he manipulates the underground assassin group known as the Twelve Heavenly Generals of the Martial Fist, duping them into acting against those protecting the city. His machinations culminate in him razing Tokyo and possessing Ryuuji, also known as Chaos, in order to obtain the power of the Black Dragon, the Yin to the Golden Dragon.

Yagyu possesses extreme knowledge and proficient martial arts, and his supernatural powers are unmatched. He is one of the most powerful magicians in the series and can absorb any damage and reflect it back on the attacker. Throughout the story, he remains a shadowy and enigmatic force, with his true origins and the full extent of his abilities never fully revealed, but his influence drives much of the conflict in the second season.