Warden of the Netherworld Prison, with Yama as My Godfather

By day, Cheng Nian is an ordinary college student. In the underworld, he's somehow become a prison warden?!

Cheng Nian: “Ugh, I have to go work in the underworld again this weekend.”

Underworld guard: “The ghost you arrested last time was sentenced to two hundred years.”

Cheng Nian: “Then I can ask him out for tea next time.”