Sometimes, sons to not live up to their father's expectations. Then again, when sons killtheir fathers, that usually doesn't make a good impression with dear old dad. This definitely sets Commodus apart from many other villains, right off the bat.
This smarmy bastard not only had a taste for destruction (he brought the vile gladiator fights back to the Coliseum), but nearly had a taste of his sister as well. He cheated, lied, and made people's skin crawl, but his jealousy for the great General-turned-Gladiator Maximus (Russell Crowe) - and his sister's desire for the same man - drove Commodus to new heights of mental instability, eventually leading to his downfall.
INTELLIGENCE - 5: He was educated but incredibly naive. Not much of a leader, like his advisory Maximus.
POWER - 5: Not particularly strong or athletically skilled. Another department where he was put to shame by the General.
VILENESS - 10: He killed his own father, destroyed Maximus' family, and then there was this moment: "Lay with me, sister."
SWAY - 6: Zero charisma, but pretty intimidating when he had to be. Just ask his sister.
PURITY - 10: Driven more insanely jealous with every move Maximus made, he was completely gone by the third act.
PHYSICAL - 3: Born with a silver spoon, he never needed to work out and it shows.