Ronny is the demon who was summoned aboard the Advena Avis. After Elmer falls overboard while chasing Szilard, he meets Ronnie who is intrigued by him and gives him one wish. Elmer asks Ronny to watch over Maiza as a human and learn how to make a sincere smile.
Ronny decides to take a human appearance and appears as the secretary of the Martillo Family to watch over Maiza as well as to fulfill his curiosity about humans.
He is capable of doing many supernatural things such as teleporting an object, stopping people's internal clock, making himself invisible, and omnipotence (he was on the top floor of a tall building and mentioned that he heard sounds "on" the first floor, meaning he didn't hear the sounds from the top floor but he was actually there).
