Ansem the Wise- Is a character in the Kingdom Hearts series and was once the king of Radient Garden. He was later betrayed by his apprentices and banished to the Realm of Darkness.
In the series he is Jake's godfather and the team's mentor. He was close friends with Jake's parents and promised them both that he would always look after him. In this series he was released from the Realm of Darkness at some point.