It seems an overwhelming majority would say dovii is the meanest , baddest cichlid you can own.
lb. for lb. tilapia buttikoferi are probably the baddest but a full grown 30 inch dovii to a full grown 14 inch buttikoferi would be a shalacking in the dovii's victory.
As for the largest cichlid in the world (temensis peacock bass , or emperor cichlid ) they would just get ripped up by the dovii.
Well I would generally say what everyone else is saying too but you said for a 100Gal tank and a Dovii, Umbee, or Jag will not work out at all in a 100G. So I would have to say that Midas, Red Devil, Trimac, Istlanum, Beani and Haitiensis (black nasty) would fit the picture for your tank just fine. But not all at the same time just a pair or solo of either species
Agree with Freshwaterpredators. 100g will only be a temporary home for a dovii, umbee or jag. For dovii's and umbee's, you will need at least a 265 for them to be comfortable. As for aggression, pretty much all of the Amphs will do the trick. Labiatus can be psycho. Citrinellus are not to far behind. Trimacs love to scrap. Festaes are str8 up nasty when adults. Take ur pick. Good luck! If ur looking for the baddest cichlid, ur tank will be empty due to the casualties.
I wouldnt say jag is on the list. heard a lot of people having jags that can live with oscars in not a very large tank. Some people say the jag is more territorial than aggressive. Have also heard that the mouth on them looks mean but is more for catching and holding larger pray. In a lip lock a RD, Trimac, Midas, RT could rip its jaw right off of its head. Heard more than one occasion of this happening. Jags teeth can leave a very deep wound but a Amphs mouth is like a pair of pliers with thorns on it.
Either way this is a topic thats been gone over time after time. Cichlids are aggressive, many types. Aggressiveness will be depended of what is in the tank. Unless you are putting huge fish in a small tank for a death match it doesnt matter. If thats the kind of thing you are into this is probably not the right place for you. My Midevil is so mean it has jumped out of the tank and bit me. Thats about as mean or more mean than I need him. Whose fish would kill whose fish doesnt matter much. (Lol I can't even open the lid without a net in my hand!)