Karin is a Senbyou (仙猫 Immortal Cat) who has lived at the top of Karin Tower for more than 800 years. The tower is located right underneath Kami's Lookout, which is a few hundred meters higher than Karin's tower and can be reached by Son Goku's nyoi-bō. Karin is a deity just below the rank of Kami, and plays a large role in Dragon Ball when he trains Goku during the Commander Red Saga to defeat Tao Pai Pai. At later points in the series and in Dragon Ball Z, Karin lends his assistance periodically to Goku and the other characters by growing them Senzu, which only grow in a tree in his tower.
He is voiced in the original Japanese version by Ichirō Nagai and then later by Naoki Tatsuta.
(Source: Wikipedia)