Complex sentence: It is known that War was killed by Mikhail Rasputin when Apocalypse invaded Russia, impressed by Mikhail's victory prompted Apocalypse to capture and brainwash Mikhail so he could joined the Horsemen of Apocalypse.
Split into simpler sentences: It is known that War was killed by Mikhail Rasputin when Apocalypse invaded Russia. Impressed by Mikhail's victory prompted Apocalypse to capture and brainwash Mikhail so he could joined the Horsemen of Apocalypse.