Grent is called "One-Handed" - so named because his right arm was cut off below the elbow by a Hilo soldier. He feels useless, unable to be anything but a cripple.
Grent's people need a leader, someone to free them from Hilo bondage. Someone who can bring them back to the gods they've forgotten. Someone who can fight for them.
And the gods have picked One-Handed to be that leader.