Complex sentence: He first grew despondent over his apparent loss, then tougher and more obsessive over crime fighting; he eventually made St. Canard crime-free with extremely ruthless methods (it's implied that he has killed people), alienating Launchpad and taking over the whole city.
Split into simpler sentences: He first grew despondent over his apparent loss, then tougher and more obsessive over crime fighting. He eventually made St. Canard crime-free with extremely ruthless methods (it is implied that he has killed people), alienating Launchpad and taking over the whole city.