There is a rumor that a ghost appears in those ruins.
He is an exorcist who vanquishes demons.
鬼 is a classic Japanese ogre or demon, usually with horns and a fierce appearance. 妖鬼 combines the kanji for 'bewitching' and 'oni', suggesting a more mysterious or ghostly demon.
Compound of 妖 (bewitching, mysterious) and 鬼 (oni, demon). The exact historical derivation is uncertain; the word is used in modern fantasy and folklore to describe a ghostly or demonic being.