Dandadan. Volume 7: Yukinobu Tatsu

A nerd must fight powerful spirits and aliens all vying for the secret power of his “family jewel,” so who better to fight alongside him than his high school crush and a spirit granny?!
Momo Ayase and Okarun are on opposite sides of the paranormal spectrum regarding what they’ll believe in and what they won’t. Their quest to prove each other wrong leads them down a path of secret crushes and paranormal battles they’ll have to participate in to believe!
Okarun and the others emerge victorious in their fight against the serpent god, but one lingering threat remains—the Evil Eye’s possession of Jiji. Even Grandma Seiko’s exorcism is of no use. To complicate matters further, whenever Jiji comes into contact with cold water, the Evil Eye regains control and attacks! Out of options, the group decides their best course of action is to watch over Jiji together until a proper exorcism can be performed—whenever that may be!