Kowloon Youma Gakuen Ki Comic Anthology: Gakuen Seikatsu-hen

Treasure Hunters - Adventurers who search for buried treasure scattered around the world. In Shinjuku, Tokyo, a young man appears as a transfer student at Kamiyoshi Academy. While he seems like a normal student, he is actually a treasure hunter. His mission is to discover a mysterious ruin hidden deep beneath the school. Accompanied by his new friends from school, he sets out to discover the mysteries of a super ancient civilization. However, numerous traps, monsters called "Kehito" that lurk within the ruins, and the clutches of the "student council" stand in his way! (Source: Arc System Works)