This is for those of you who have not the first clue about Evangelion. If you ever want to actually see the series (dooo iiiiit! It rocks in a freaky weird shit way!), I advise not reading it because of the spoilers from hell. Entirely Asuka centric.
Asuka:
-Is a 14-year-old redhead with the Issues from Hell.
-Showed up in Episode 8, on an aircraft carrier somewhere in the Pacific Ocean.
-Made a great first impression by slapping all males within reach when her skirt accidentally blew up.
-Immediately pronounced Shinji (14, main character, introvert) boring.
-Has a big huge crush on Ryoji Kaji (late 20s, works for NERV, technically a spy). Glared death at Misato (late 20s, commander of military ops for NERV) when informed that she was Kaji's ex.
-Is very proud of Evangelion Unit 02, and took the first opportunity to inform Shinji just how great it was.
-Dragged Shinji into the entry plug with her when an Angel attacked. They bickered constantly up until the critical moment, when it took both their strength to operate the EVA underwater.
-Moved in with Shinji and Misato, and proceeded to criticise most everything Japanese.
-Quickly became the most popular girl in school, and told Rei (1st Child, acts like a robot) that they should be friends because it would be convenient.
-Rushed into battle when the next Angel showed up, and blamed Shinji for the two of them getting owned and NERV getting humiliated. Had a loud argument about that right over the top of their debriefing session.
-Was forced by Misato to live and work with Shinji so that they'd learn to synchronise their movements. Did not take this well.
-Was shocked and horrified when Misato suggested replacing her with Rei, and ran off in a huff. Refused to let anyone take her place, ever.
-Blamed Shinji again when their EVAs ended up in a compromising position after they defeated the Angel.
-Teased Shinji fairly explicitly while 'helping' him with his homework - in a bikini ("If I warm up my breasts, will they get bigger or smaller?").
-Was horrified by the enormous suits she and Unit 02 had to wear to dive into a volcano after an Angel, but refused to let anyone else take the mission.
-Thanked Shinji and actually sounded grateful when he saved her life after the mission went tits-up. Was back fighting with him within hours.
-Insisted on being the 'leader' when the pilots had to find their way into HQ during a power cut, even though she didn't actually know the way. Made Shinji do all the grunt work, and said some really bitchy things to Rei, who remained disappointingly unresponsive.
-Insisted on taking the most painful and dangerous position in a fight because she 'owed Shinji a favour.'
-Is disgruntled whenever Shinji has the 'luck' to be in the primary position against an Angel, and does her damndest to take over the fight if possible.
-Absolutely hated being helpless in the face of danger.
-Refused to even contemplate letting anyone else pilot her EVA.
-Kissed Shinji out of sheer boredom, and immediately regretted it, blaming him.
-Called Misato and Kaji's resumed relationship 'disgusting' and improper.
-Reacted to Shinji's high sync scores by provoking him into attacking an Angel outright. Blamed him for trying to one-up her when it swallowed him. Was kind of sickened when Unit 01 went berserk again and tore the Angel apart from the inside.
-Is friends with Hikari, a gentle girl from school. Is very shocked to discover, via Kaji, the identity of the Fourth Child.
This is the point at which I had Misato and Kaji go to the US to investigate the destruction of the Second Branch. Asuka tagged along because she couldn't stnad the idea of letting them have all that time alone, and Misato packed her off to camp because she got annoying.
More canon, purely for reference. Movie endings, because the series ending is all in Shinji's head anyway.
After ep17, Asuka:
-Gets completely owned (within microseconds - she has time to shriek and that's it) by Unit 03 when it turns into an Angel.
-Is sent to fight an Angel that breaks into HQ, and gets owned again. The arms get torn off her EVA (owwie) and then its head flies off and nearly crushes Shinji, and she collapses helplessly in the entry plug.
-Is stunned and disbelieving when Shinji is absorbed by Unit 01 after it goes berserk again and eats the Angel.
-Has a Very Bad Period and loses most of her sync ratio. Becomes hysterical at Rei, slaps her, and screams that she isn't a doll, she's in control of her own life.
-Launches against orders to fight an Angel, but gets mindraped by it instead. Has flashbacks to some serious trauma in her past that she's always refused to remember, including her mother's insanity and being referred to as a doll.
-Refuses to go home and stays at Hikari's house, in a severe depression.
-Is sent to try and help Rei against the 16th Angel, but cannot sync with the EVA at all. Is very upset that Unit 01 is taken out of cryostasis to save Rei, when NERV wouldn't do that for her.
-Refuses to believe that Kaji is dead.
-Remembers finding her mother's body after she'd hanged herself. Just when little Asuka was so excited about being chosen as an EVA pilot, too.
-Runs away and is eventually discovered by NERV Intelligence naked in a bathtub in the ruins of Tokyo-3, muttering about being a total failure. Opinions differ, but the blood in the tub and the bandaged arms in the hospital look to me like she tried to kill herself.
-Goes into a catatonic state in the hospital. Is eventually shoved into the entry plug when HQ gets attacked, and Unit 02 is hidden at the bottom of the lake.
-Has some flashbacks of her mother, wakes up the EVA, and realises that her mother's always been there with her. Happy!Asuka.
-Fights the UN forces and the EVA Production Models with just the power in Unit 02's batteries. Goes seriously berserk, but owns them. Until they all come back to life and dismember Unit 02, anyway. Did I mention the pilot feels the EVA's pain? Yeah.
-Ends up lying blank-faced on the shore of the LCL sea after that whole Apocalypse-but-not, being strangled by Shinji. Except not fatally. We hope.
What's Really Going On, ie the stuff Asuka doesn't know. Because in-jokes are my joy.
Oh boy. A lot of this is my interpretation of stuff that's very very vague, okay?
SEELE are a bunch of old men with an obsession with Judeo-Christian mythology, and they don't want to wait until Judgement Day. They want their Promised Glory now, damn it. So they engineer it. They form a puppet organisation, NERV, under the control of Gendo Ikari, and in the year 2000 they succeed in reducing Adam, Angel #1, to its component parts. Its body is reduced to an embryo, and SEELE puts its soul into a human-shaped clone.
The result of the reduction of Adam is a catastrophic explosion which melts Antarctica and wipes out at least 50% of the Earth's population, but SEELE aren't all that bothered because hey, Promised Glory. The Evangelions are made as copies of Adam, but they need souls. The souls are from women who died in the experimental stages, and the pilots chosen for the EVAs are the children of these women.
The Angels attack NERV because underneath HQ is a giant crucified statue, which everyone pretends is Adam. Actually, it's Lilith, the ancestor of humanity. Whether the Angels want to destroy Lilith or join with it is pretty much speculation, but either way it would destroy humanity. Most people don't think much of that idea, for some reason. After Ep 8 NERV also have the embryonic body of Adam, which is implanted in Gendo Ikari's hand and looks really gross.
Incidentally, the reason Unit 01 goes berserk all the time is because Yui Ikari's soul is in it, and she's defending her poor little baby son Shinji.
There is much double and triple and quadruple crossing between SEELE and NERV. It's complicated.
The final Angel turns out to be that human-shaped clone SEELE gave Adam's soul to, and he kind of falls for Shinji. It's unbelievably cute right up until he betrays them all and tries to join with Lilith. No, I tell a lie, it's still unbelievably cute. Except he decides that he'd rather Shinji have the benefit of deciding the fate of humanity, as if the poor boy wasn't messed up enough. It's all Very Tragic. And angsty. And damn it Ode To Joy is supposed to be joyous.
SEELE invades and slaughters everyone. Rei turns out to have Lilith's soul, and joins with its body, kickstarting that Instrumentality thing they've been talking about all series. Seems that's what SEELE are calling their plan for the Promised Glory - a sort of Teilhardian 'let's force humanity to evolve and dissolve so that we can all be united and have no more barriers' thing. Unit 01 gets crucified on the Tree of Life to aid in this procedure.
Shinji gets stuck with the big decision, and says well hang on, barriers aren't so bad if people can love each other and whatnot, and this is all way too freaky. Back to normal, plskthx. And that's basically it, bar the strangulation and giant heads falling into the sea.