Sekai ni Hitori, Zenzokusei Mahou no Tsukaite

In another world, Zenichi Kiyama was just an ordinary office worker until a tragic accident sent him into the afterlife. Reborn as a baby in a strange new realm, he was tested for magical potential—only to be labeled with the dreaded “dark attribute.” Now, feared as a demon child, he must navigate a world that sees him as a threat.