Complex sentence: The later games present MacTavish as an NPC (Non-playable character) that the playable character fights alongside; however in' the player takes control of MacTavish in the final three missions.
Split into simpler sentences: The later games present MacTavish as an non-playable character (NPC) that the playable character fights alongside. However in' the player takes control of MacTavish in the final three missions.