The Great Cleric 5

Luciel has made fast progress in his new role as Exorcist thanks to all the training he had already done with Brod. As he continues making his way through the underground Labyrinth, he'd like to take his training even further, provided it doesn't interfere with his duties. Lumina conveniently offers to help, but her proposal isn't quite what Luciel expected—

Volume 5 of The Great Cleric manga series by Hiiro Akikaze.