Complex sentence: He is later featured as the protagonist of "Metal Gear Solid" prequels where he is depicted as an American covert operative and decorated war hero that later turns into the leader of a rogue band of mercenaries.
Split into simpler sentences: He is later featured as the protagonist of "Metal Gear Solid" prequels where he is initially depicted as an American covert operative and decorated war hero. He eventually breaks away from the group, becoming the leader of a rogue band of mercenaries.