Kiv

Kiv was the leader of the Mentors, a group that included Sil

Biography
Both Kiv and Sil became rich via profitable deals. He became involved in weapons dealing with the primitive peoples of the planet Crontep. He complained of pains in his head that was a result of his brain expanding. Surgery was performed and his brain was moved into that of a similar mentor. This was not perfect however and so again surgery was performed to move his brain to the body of Peri. He was killed by King Yrcanos. (DW: Mindwarp)

Accuracy
Due to The Matrix being altered elements of Kiv's biography may be incorrect. Most likely incorrect are areas where the Doctor's actions effect those of Kiv. (DW: The Trial of a Time Lord)