Teeki is a Forbidden Magic Law practitioner who is at least 800 years old and a member of the Forbidden Magic Law association Ark.
Born Edward Teek, Teeki was originally a Magic Law practitioner. He was chosen for something, but was casted out by the Association. Enraged, he donned the mask that he wears and swore to make the Association pay. He discovered a method that allowed him to resurrect himself over and over, allowing him to basically become immortal. Sometime, he met with Isabi. According to Isabi, Teeki used to do things like making Mt. Fuji erupt, releasing 100,000 evil spirits on Kyoto, and making the entire Taira army disappear. Teeki and Isabi occasionally fought each other, and were evenly matched.
Teeki ended up watching two specific boys: Muhyo and Enchu. He would use one of them to resurrect himself. Both were struggling against one another, trying to become an Executor, and Teeki knew that this would cause both of them to become stronger. When Enchu lost, Teeki killed Enchu's sick mother, driving Enchu over the edge, allowing Teeki to take advantage of him. Teeki used Enchu to resurrect himself and taught him Forbidden Magic Law.