battler

/ˈbætələr/

noun

A person who battles or fights.

But the credence of his claims was reinforced by the fact that the Brockton-born battler was smaller in stature than most he fought.

advocate,proponent,promoter,proposer,supporter,standard-bearer,torchbearer,flagbearer,defender,protector,upholder,backer,exponent,patron,sponsor,prime mover