Rasa

The was the previous leader of Sunagakure. He is the father of Temari, Kankuro, and Gaara, and husband of Karura.

Background
By his design, the One-Tailed Shukaku was sealed within Gaara so that he could become the village's ultimate weapon. However, as Gaara grew and his abilities began to manifest, the Fourth realized that this had been a poor choice and started to view Gaara as a failed experiment who was a threat to the inhabitants of Sunagakure. In time, the Fourth began issuing orders for Gaara's assassination, none of which were ever successful.

Abilities
His level of strength is not shown but given he was selected to be the Kazekage, it can be assumed he possessed some power. However, considering how easily Orochimaru defeated him, it is presumed he was fairly weak (though at that time, Orochimaru was very powerful, capable of besting the Third Hokage).

Invasion of Konoha
The Fourth was also the one to join with Orochimaru in his attack on Konohagakure, hoping to teach the daimyo a lesson and to re-establish the Sunagakure's military force. Things, however, did not go as planned for him; just before the Chunin exam's third stage, where his attack was planned to take place, he was betrayed and impaled by his ally, Orochimaru, who stole his identity. Ironically, the son whose life he made miserable, Gaara, becomes the new Kazekage in his place.

The Fourth Kazekage was seen once more in flashack of Kimimaro where Orochimaru was seen stabbing him thus killing him. Kabuto and Kimimaro were at the site.