Shinigami Mina no, Shiseikatsu.

Imase Kyouya, a high schooler who can see what others cannot—‘non-humans’—has lived a lonely life because of it. Determined to start fresh and make friends, he vows to avoid the supernatural at all costs. But his resolve is shattered when Mina, a self-proclaimed ‘strongest shinigami,’ suddenly appears to claim his soul.