Both demasoni and lombardoi are considered agresive,
Maylandia Lombardoi are usually called kennyi if that rings a bell
However in my experience the lombardoi is the boss of the tank but not responsible for any deaths besides one female which was entirely my fault (2male:2female ratio, and the dead fish had breed three consecutive times with less then a week in between)
If you give em space they shouldn't be a problem. The lombardoi is my favorite fish it seems to be so much sarter then the other mbuna and very personal, right now he's going crazy up and down the glass constantly cause he killed that female and I removed the other one till I could get more he's just bored
Demasoni are extremely agresive to similar looking fish, especially their own species keep extra females with them