And so, Tricky Tricky was born.
He travels the universe making deals with life forms who are on the verge of death, when they are at their most... vulnerable to persuasion. He promises them new life but in actual fact he neglects to tell them that, in being saved, they become his slaves.
He can also manipulate people into doing what he wants. For example, when the Doctor's companion Sarah Jane Smith was a girl, she witnessed the death of one of her friends at a pier. Because Sarah is always outwitting the Tricky Tricky, he appeared to the Girl on the pier as she clung on for dear life and convinced her to allow him to switch her and Sarah so she would die instead. Desperate, she agreed. Luckily, Sarah's friends in the present day still remembered her as she was and they were able to rewrite time.
He then again tried to defeat Sarah Jane by setting up a false wedding, with the groom being used by Tricky as a means to hurt Sarah Jane. However, with help from the Doctor, the groom reconciled and broke his deal with the Tricky, ending his own life in order to save his love. Aww. And thats not all either, Tricky Tricky is being constantly defeated by Sarah Jane, but that doesn't mean he is a failure. He has an army of Time-Altering minions that corrupt time to his will, and he has even battled the Lord of Time, Dialga, head on.