the emperor cichlid from tanganyka although idk if it is considered a hap.as far as Malawi-tangerine Tigers can be mean,but in reality it seems like it comes down to individuals.Every litter is going to have one or more dominant fish.these 'picks of the litter' can be more aggressive.Hypothetically speaking if you added a more aggressive species or one that is thought to be,to a tank with not as aggressives,it might work if you used a sub-dominant one.
Also I've seen a front maul a fusco,but the fusco started it.these were jumbo sized.they lipped up and the front body slammed him repeatedly.After all the others saw the previously dominant fusco weakened,they jumped him and killed him.
I've heard ahli's are also aggresive ,but had 3 and none were to bad.