In Final Fantasy X, Kimahri is a Ronso from Mount Gagazet. His horn was broken during a childhood fight with fellow Ronso Biran and Yenke. He is a guardian of the summoner Lady Yuna, and accompanies her on her pilgrimage to all of the various temples of Yevon in Spira, as she tries to achieve the Final Aeon and thus defeat Sin.

His celestial weapon is the Spirit Lance, which may be obtained by completing the Quactuar Quest on the Thunder Plains. Once you have done this, you need to Saturn Crest and Saturn Sigil to give the Spirit Lance its full potential.

I personally like Kimahri - he doesn't talk much, but he is a pretty decent fighter. Plus, if you use his Lancet ability, you can learn the special attacks of various fiends, such as Stone Breath and Mighty Guard, to name just a few.