Complex sentence: Corax and his Legion fought under the command of Warmaster Horus for a time, but the two Primarchs did not see eye-to-eye, and only avoided bloodshed when Corax removed his Legion from under Horus's command.
Split into simpler sentences: Corax and his Legion fought under the command of Warmaster Horus for a time. But the two Primarchs did not see eye-to-eye, and only avoided bloodshed when Corax removed his Legion from under Horus's command.