“Go! Black-Eyes Blue Prinny!”
—Se-to-oh, Disgaea 3: Absence of Justice
Appearing in the post-game content, Se-to-oh is a member of the infamous Diez Gentlemen, and boss of a post-game event as part of the Diez Gentlemen encounter battles that can be unlocked through passing Homeroom topics. Se-to-oh is a name parody of Yu-Gi-Oh! (a popular anime and manga franchise), and the name seems to refer to Seto Kaiba (a character of the series). During the initial story scene portion of the encounter, he makes frequent references to the series, even sacrificing three monsters to tribute summon a "Black-Eyes Blue Prinny" (a reference to the Blue Eyes White Dragon, a well known monster in the Yu-Gi-Oh! series, which is used mainly by Kaiba).