Lugh is immortal. Not exactly immortal but has regeneration which is insanely fast! Almost 20× faster then normal human. Ugh, so he is kinda unique. He has no spiritual energy in his body which technically is impossible. Even a dead  person has a spritual energy you know! Is he even existing? After his parents passed away when he was 10, he started living with his grandma who technically is suffering from immortal youngness and his sister ( Adopted by Grandma ) who is a scholar student in middle School and karate asperint. They all are exorcist including Lugh and Mai. He meets with his Chinese Aunt and Mai who is his classmates . . . .  They live together by the way. Circumstances makes them join the same Literature club. Lugh, a coward clinging in his past, one day will save all of the club members or even lots of people from death but it'll be spoiler if I spilled it out (｡•̀ᴗ-)✧