Who is Kincaid from The Ox-Bow Incident and what is their importance?

Kincaid is a young, dark Irish man who works as a cowhand on Drew's ranch. Kincaid is a quiet, unassuming man who has apparently made a lot of friends during his time at Drew's. The word of his death inspires Farnley to vow to avenge his death, leading to the vigilante mob that hangs Martin and his two cowhands. However, it turns out Kincaid was never dead.