Yes, the Zemo I'm referring to, Helmut is the son. But still his list of accomplishments are nice. Led a Masters of Evil, succesfully invading Avengers Mansion (Siege of Avengers Mansion storyarc, Hercules is beat into a coma, Jarvis is almost paralyzed, beats and tortures Cap), made Captain America cry, created the Thunderbolts, took over the world, sapped all of the trans-normal energy from it's various sources all over the world.
and yet still managed to recieve semi-regular ass kickings then got wasted (killed) by scourge AKA nomad......... of course he was later brought back to life through a plot twist (something we've never seen before in the field of comics......... located right between the field of dreams and the field of corn)
still i'd have to go with zemo, he picked up a few skills pretending to be citizen v and is an expert swordsman and not bad on his V-wing either
Whose ass could Scourge not kick? With the arsenal at his disposal, the element of surprise, etc. I was surprised Zemo lasted as long as he did. And his coming back is antoher thing, he helped to create the "mind modem" or something like that, so his brain engrams can be downloaded into other bodies.