Dovii and Umbeee meanest and bad assI would say dovii, they get bigger, stronger, and have better equipment...and seem to have more of an inclination to use them. I've seen cichlid comm's with butti's living somewhat peacefully, something you rarely if ever see with adult dovii.
What about umbee?
My vote would be a male dovii as being the most aggressive in my experience. However the male Butt is very close.
In large tanks like mine both mellow out and once dominance is established years go by without much aggression.
Placed back into smaller tanks under 500 gallons both of their aggressive natures return.
My smaller Dovii male in the 52 (17") was always more aggressive than my 22-23" male in the 15. The bigger Dovii died in 2009 after being killed by the 26" black shark (Not a fair fight as the old Dovii was very long on the tooth..pun intended).
The smaller Dovii is still doing well in the the 52.