During a lightsaber duel, Sidious kills Opress and defeats his former apprentice but leaves him alive, though, as he may be useful in the future.
Sidious kills Opress. This is during a lightsaber duel. This is though. Sidious defeats his former apprentice alive. This is during a lightsaber duel. This is though. He may be useful in the future. Sidious kills leaves him alive. This is during a lightsaber duel. This is though. He may be useful in the future.