Sein Kami (セイン・カミ, Sein Kami) is the primary antagonist of Kamisama no Iutoori Ni, he is Kami-sama's counterpart. As "God Jr.", it's his job to test the "trash" who skipped school to see who's worthy of God's power.
A very mischevious, creative and intelligent child who enjoys watching anime and people dying. Easy to provoke with a quick temper, he'll kill anyone he sees fit to prove a point.
He first appears in Chapter 5 as he introduces the students to his "Kamiculum", designed to test everyone who skipped school and missed the games by forcing them to participate in their own. He demonstrates his power by using his voice to blow up a dissenter's head, instantly quelling the crowd. With a short celebration, he announces the start of Harau Haru Harao and disappears.
He is seen during the test tinkering with a toy xylophone, commenting on Kai's voice and saying that the students aren't seeing the full scale of his first test.