The son of the man who invented the arc reactor alongside Howard Stark and got nothing for it.
Ivan Vanko is the best idea Iron Man 2 has. His father Anton designed the arc reactor alongside Howard Stark and was deported and forgotten, and Ivan builds the same technology in a flat with no money and takes it to Monaco.
The film then loses interest in him and hands the second half to Justin Hammer’s drones, which is a shame, because the argument Vanko is making is the one the Iron Man films never quite answer: the technology belonged to two people, and only one family got rich.