12 : To You, Someday Now
This episode solidified Mahito as a major villain by showcasing his pure malice. Reviewers from Star Crossed Anime and But Why Tho? note that Mahito represents the worst of human cruelty, acting as a direct foil to Yuji’s selflessness.
Early in the series, Yuji strives to ensure people die a "proper death" without regret. Junpei's death—manipulated, painful, and senseless—is the antithesis of this ideal, forcing Yuji to confront the harsh reality that he cannot save everyone. 12 : To You, Someday
The episode establishes why Yuji is Mahito's natural enemy; as a vessel for Sukuna, Yuji is subconsciously aware of the soul's shape, allowing him to bypass Mahito’s defenses and strike his soul directly. Critical Reception Re-Watching Jujutsu Kaisen's First Season - Anime Rants This episode solidified Mahito as a major villain