Jin Bi-wal is the friend of Dong-young and attends the same high school. They are very close and are often confused by other students to be homosexual or "boy-lovers". He is the only character who suspects Dong-young to be the Princess. He sometimes likes to grope Dong-young even after "finding out" that she was a girl (he had already known that she was a girl before he accidentally saw her bound chest). Bi-wal is also shown to be something more than a human (as he seems to have a great deal of power by killing a nymph to save Dong-young and is also a fiancé of a noble from Hell) and has a hidden agenda regarding Dong-young. Later in the series, Bi-wal is said to be the real King of Hell. Bi-wal and Doung-young knew each other since their childhood, but Dong-young doesn't remember it and the promise they made. He also shows love for Dong-young.
He has many personalities, and is rather funny and laid back in the beginning. When his brother or Dong-young are involved, however, he became more serious. During the rescue of Dong-Young's kidnapping, he tells his brother that he stayed with her because he knew that Ryung-Jin would some time approach the Princess, and it would make it easier for him to find Ryung. He goes on to say that he thinks Dong-Young to be nothing more than a tool to manipulate. However, he says this to try to get closer to his brother and actually loves the princess. Once Ryung agrees to make peace, Bi-Wal returns to his post as King of Hell. He marries Dong-young when she becames Lord of Heaven and together, they live in a palace in the demon world.