A Whole New Meaning to the Phrase "Earworm"
As villains go, it's hard to top Khan Noonian Singh for pure buttoned-up fury. He's an angry, angry man when we first meet him… and he looks even angrier than when we saw him in the original Star Trek episode "Space Seed."
But one of the great things about this movie is that you don't need to have seen the earlier episode to get where Khan is coming from. They get you up to speed quick and then let the man do his thing.
And by "do his thing," we mean, "be a psychopath armed with squicky space-worms."
Khan began life as a genetically engineered conqueror who controlled over one-quarter of the Earth in the dangerous future of the early 1990s. (We know, we know. This movie is so 80s it bleeds Aqua Net.) Eventually deposed, he and his followers escaped by boarding a spaceship in cryogenic storage, hoping for their lot to improve in the reaches of space.
It didn't. They got revived by the crew of the Enterprise, and Khan responded by trying to kill Kirk and take the ship. Kirk, never one to be outdone in the "take the law into your own hands" department, exiled Khan and his followers to a desert planet, where they could eke out a rough living.
You Say "Revenge-Crazed Megalomaniac" Like It's a Bad Thing
Now here's the thing: Khan's crew didn't go alone. One of the Enterprise crew—Lt. Marla McGivers—fell in love with Khan and helped him try to take over the ship. When the dust settled, she went with him to Ceti Alpha Five: giving up paradise in the Federation and a snazzy Starfleet career to fight dust storms and suck moisture out of the local plant life.
She gave up everything for him…and for that, she got to die sometime after they were exiled when one of those Ceti eels crawled into her ear.
KHAN: What do you think? It killed twenty of my people, including my beloved wife.
It was an ugly way to go, and Khan isn't the kind of guy to forget about something like that. When the planet shifted its orbit and nobody came to check on them, he basically had nothing to do but stare at the walls and plot all the various ways he could brutally murder the guy who put him there. Namely: one James Tiberius Kirk.
And when one turns an intellect as big as Khan's towards revenge, things get dangerous.
At Least He Loves His Wife?
That thirst for revenge comes across as a deep wellspring of passion, reflecting the passion he felt for his dead wife. (Ricardo Montalban goes into some detail on it during an interview for the film, which you can peep over in the "Best of the Web" section.)
His need to carve off a piece of the man supersedes everything else. He and his gang escape—by hijacking another Federation ship, more successfully this time—and basically can do whatever they want after that.
But Khan isn't interested in doing anything but putting Kirk in his place. None of the tempting possibilities of escape—building a new empire/blackmailing governments with the Genesis device/eating ice cream for the first time since the 1990s—appeal to him, because he makes Liam Neeson look like a mild-mannered forgiveness-happy bloke:
KHAN: He tasks me. He tasks me and I shall have him! I'll chase him round the moons of Nibia and round the Antares maelstrom and round perdition's flames before I give him up!
That last bit is a riff of Moby-Dick…a little book about a man who's too obsessed with vengeance to know what's good for him. And revenge-thirst is the most notable feature of Khan's personality.
Just take a look at how dogged his quest for vengeance is…even when the Enterprise has him basically cornered:
KIRK: This is Admiral Kirk. We tried it once your way, Khan. Are you game for a rematch? Khan? I'm laughing at the "superior intellect."
KHAN: Full impulse power!
JOACHIM: No sir! You have Genesis. ... You can have whatever you...
KHAN: Full power! Damn you!
Sure, Khan's strength and intellect make him a scary bad guy, but his thirst for vengeance ultimately forces him to essentially sign his own death warrant. But this character trait is also the thing that makes him human, what turns him from a cartoonish supervillain to someone whose actions are made understandable.
He is, in short, a villain worthy of challenging Kirk to a duel to the death…and a character who turns this space opera from a good yarn into something really epic.