Most evil character in Iron Man 2

Re-watching Iron Man 2 I don't think either Justin Hammer or Ivan Vanko are as evil as most of the other villains in the MCU (excluding Trevor Slattery who's barely even a villain). Hammer was only directly, or even indirectly, responsible for one character's death (the patsy prisoner who replaced Vanko, and for all we know he could have been a murderer awaiting rendition to a country with the death penalty anyway), and showed genuine concern when Vanko's drones started shooting up the Expo and endangering lives (even if his primary consideration was his own reputation).

And even Vanko, who did kill a couple of Hammer's security guards and most likely caused a fatality or two at the Monaco Grand Prix, was not focused on any more malign or grand a scheme than getting revenge on Tony Stark, admittedly by killing him. His goal wasn't to take over the world or profit from the killing of innocents (as per Obadiah Stane and Aldrich Killian). He just wanted a single man, Stark, dead.

Obviously, I'm not defending the motives or actions of Hammer and Vanko, particularly the latter who didn't particularly care if bystanders died in the process; they're still bad guys. But in the grand scheme of the MCU, they're two of the least destructive or evil villains.

So the real bad guy of Iron Man 2, the guy who was affiliated with a genuinely malign, powerful and oppressive organisation, was in fact the guy who awards Tony and Rhodey medals at the very end of the film, Senator Stern, member of HYDRA.