"Through hate, all things are possible."
- – Malus Darkblade
"An encouraged person will eventually get his drive from encouragement; he becomes more dependent. A person that never really receives encouragement learns to move out of spite; he becomes more independent."
- – Criss Jami
Malus Darkblade is a hard tough bastard who simply won't die. Putting them other fantasy characters to shame, while he may be selfish, arrogant, wicked, and basically everything you would expect from a Dark Elf, he is actually portrayed somewhat believably as well in the five novels written of him by Dan 'All hail the great one' Abnett and Mike Lee. He showed moments of comradeship and faith towards his companions and wasn't made out to be evil for no more reason than because he could be.
He is one of the most popular WF characters then because he has that rarest of qualities; actual character. His refusal to give up and his hard as nails approach at slaining anything that gets in his way has made many fanboys hold a torch for him. If he wasn't a pansy elf and a dark one at that, he and Gotrek would be firm drinking buddies.
Malus comes from a series of comic stories from the days when GW actually cared about making a good story without making it serve a purpose like realising new models. His soul stolen by a daemon when he was questing for treasure, he had to find five artefacts in order to free the daemon and himself, only for the daemon to steal his soul when it was freed.
Wandering the chaos wastes as a soulless unstoppable killer, he then found out where the daemon was hiding and went on another quest to reclaim his soul, doing so but then being cursed to have the daemon trapped back inside of himself again.
Now he has returned to Naggaroth and what will this strange, legendary dark elf do? Well GW is coyly stopping us answering that question, because they won't move the damn plot along and let Malus kick Malekith's tin ass! Except where he returns to fuck his sister and try to assassinate the Witch King in the End Times. Typical Druchii fashion, that goes as well as expected.
Be careful what you wish for because, unfortunately, he'll never get the chance now. During the final invasion of Ulthuan, Tz'arkan takes over and consumes him so he dies, causing him to be ripped apart from the inside out. No Malus! Don't go, we liked you.....cue fan boys grieving.