Starchaser: The Legend of Orin/YMMV

Complete Monster: Zygon. Formerly a rogue android known as Nexus, his first attempt to take over humanity was stopped by guardians known as the Ka-Khan. Forced into hiding, Zygon bides his time and establishes a slave mine on the planet Zinia, forcing human slaves, regardless of age or physical condition, into working in such harsh conditions they often die. The blade the Ka-Khan used to defeat him is found by an old slave, who's killed to keep it a secret. Once Orin finds out about the blade and decides to escape, Zygon fatally strangles his girlfriend Elan. After Orin escapes, Zygon places a massive bounty on his head and has his Mecha Mooks attack him at every turn. He captures Dagg and has him painfully tortured by shooting a laser into his forehead, overseeing it with a sadistic grin. After he has the heroes within his grasp, Zygon leads his ships to obliterate the human's opposing fleet and take over the planet by force. Once he's been revealed as Nexus, Zygon takes Aviana (the new love interest) hostage, threatening her life. Once Orin surrenders, Zygon attempts to strike him down with his own blade. Cocky, arrogant, and lacking in empathy to the very end, Zygon was as remorselessly cruel as an Evil Overlord could be.
Hilarious in Hindsight: Despite the film's clear attempts to capitalize on the success of that other space opera classic, there is a scene in which the main hero cuts through a metal door with his Laser Sword and another where the Dark Lord falls down a large pit after being sliced horizontally in half with it. Coincidence?
Unfortunate Implications: Dagg turns Silica from bitchy to flirty by probing the "personality circuits" in her ass without her consent. Rape Is Love anyone?