Complex sentence: Cowboy was used by Amalgam to get at Steel by attacking his family--thus, Cowboy betrayed Jemahl again, beating up Blondel in a mugging and shooting Jemahl's foster brother, Tyke.
Split into simpler sentences: Cowboy was used by Amalgam to get at Steel by attacking his family. Thus, Cowboy betrayed Jemahl again, beating up Blondel in a mugging and shooting Jemahl's foster brother, Tyke.