Kiv helped the Mentors become rich from profitable deals, and was worshipped by many members of his race, particularly Sil. He was involved in weapons dealing with the primitive peoples of the planet Krontep in 2379.
Kiv's great intelligence and business expertise were likely due to his mutated brain, which was vastly larger than the brains of most other Mentors. However, Kiv's brain did not stop growing larger as he got older, and later in his life, his brain was compressed against his skull, which caused him severe pain and would have eventually resulted in his death. To prevent this, he hired the scientist Crozier to find a way of transferring his brain into a host who could hold his expanding brain without trouble.
The first operation performed by Crozier moved his brain into the body of a similar Mentor, albeit tan-coloured and with a stinging barb. Kiv's second body held the brain for a bit longer but was not a perfect solution - not least due to the fact that the mind of its original owner, a fisherman, kept influencing Kiv's business decisions.
According to the Matrix, when the brain started getting too large for the second body, Crozier tried a different technique and transferred Kiv's consciousness directly into the body of Peri Brown, destroying her original mind and removing the problem of Kiv's constantly expanding brain. Shortly afterwards, however, King Yrcanos, who had fallen in love with Peri, broke into Crozier's laboratory. Discovering what had happened to her, Yrcanos apparently killed everyone there, including Kiv. (TV: Mindwarp)
However, according to another account, Kiv in fact survived and underwent further brain transplants, eventually ending up with the body of a human lawyer. Keeping his true identity secret from everyone but Sil, he defended his old associate when he stood trial for introducing a dangerous drug to Earth. (HOMEVID: Sil and the Devil Seeds of Arodor)