"The Poet" is Lamia's resident wannabe gentleman. As his name suggests he is very fond of poetry and likes to recite them at any time given, and much to everyone's dismay, he happens to recite them or make his conversation into a rhythmic banter pretty much any time he opens his mouth. Graham seems to be the only one who appreciates his poetry. (Source: TV Tropes)
Doi's landlord, who considers him a troublemaker. He's been known to try to renting out Doi's house to other people during terms when Doi stays at the academy. He also doesn't know about Doi and Kirimaru's identities as ninjas, and they work hard to keep it that way.
The eponymous devil of the Devil Ring. In the past, he was the last King of the Shang Dynasty, King Zhou of Shang, Dixin.
He doesn't seem to have a name but Kirihito once referred to him as "Man with a scar on the right side of his neck." He rapes and kills Tazu, and later tries to exploit Urabe and Izumi's fake engagement for profit.
A pretty girl who has a disgusting tendency to pick her nose and eat the booger afterwards or flick it into the pool. She is a member of the Girl's Water Polo team and has a easy-going attitude.