Who is Santos Tirador from Dogeaters and what is their importance?

Santos Tirador is the head of the National People's Army, the NPA. He lives in hiding in the mountains, but he regularly returns to Manila to see his beloved, the beauty queen Daisy Avila. Santos impregnates Daisy early in the play before fleeing back to the hinterland. After Senator Avila is assassinated, Daisy is informed that Santos has been killed and mutilated.