Complex sentence: Mordru (as Monarch) then kidnapped Hawk and Dove, killing Dove's boyfriend and putting her into a comatose state drove Hawk insane with false memories of "Monarch" killing Dove and being killed by Hawk, who's face was behind the Monarch mask.
Split into simpler sentences: Mordru (as Monarch) then kidnapped Hawk and Dove, killing Dove's boyfriend and putting her into a comatose state. He drove Hawk insane with false memories of "Monarch" killing Dove and being killed by Hawk, who's face was behind the Monarch mask.