Shinji is the main character in the story. In the first episode he is re-united with his father, who left him, he finds his father only wants him there to pilot EVA 01, he doesn't want to do this, but Rei's injuries change his mind.
He is a very insecure person, tells himself alot to not run away from his problems, he feels that people do not like him mainly because he has been dumped by his father he is scared of being rejected again. He is a quiet person and tends to listens to his walkman to get away from things.
Shinji has a thing for Asuka, we see this when he goes to kiss her when she was asleep, and when she lets him kiss her.

Rei Ayanami

Rei Ayanami is the first ever pilot for NERV, she tested EVA 00.
She is quiet and tends not to show any emotion to anyone. She has no friends in and out of school the only person she talks to is Gendou.
The only other emotion she has made to anyone is Shinji when he opened the entryplug to get her out and she smiled at him, it seems that she feels good with these people because she can see the care for her.
We find out later that Rei is a clone of Yui Ikari (Shinji's mother).

Asuka is the pilot of EVA 02, the first production model of EVA.

She is very loud and bossy, she is very involved in her own image and how she looks and acts. She always wants to be the best pilot and when Shinji become a better pilot than he in much shorter time it gets to her.

You find out that her mother Souryu Kyouko Zeppelin, her real mother fell into mental breakdown in an accident during an experiment. She committed suicide.

Her soul was used as the core of EVA-02.

Tohji is not a very big character, he is first introduced as the brother of a girl who was injured in EVA 01 first battle against the angel, when he finds out Shinji is the pilot he hits him.

He cares so much for his sisters in hospital because he visits her everyday. He later regretted this because he found out how hard it is for Shinji to pilot EVA 01 and the responsibility.

He became the pilot of EVA 03, a black EVA, a production model like EVA 02, this was invaded by an Angel and he lost a leg and an arm. He wasn't seen after this.

Misato Katsuragi

Misato took on the role of guardian for Shinji, when he came to Toyko-3. At first she comes across as a very outgoing person, but we find this took her along time to achieve.

She was the only survivor of the expedition team to Antarctica, her father when he put her in a protective container just before the second impact occured. Which he was killed in.

She hates the angels and joined NERV to take her revenge on them.

Kaji was Misato's boyfriend in college. Kaji, Misato and Ritsuko used to go out together while they were in college. We find out he is a spy sent by the Japanese government to find out what was going on in Nerv.

Ritsuko is the technical supervisor for the project and knows much about what the Evangelions are, more that she is telling Misato anyway. She took over the position of her mother, Naoko Akagi she constructed the three magi, Casper, Melachior and Belthazar which represents much of the internel struggle going on in herself.

Naoko Akagi is Ritsuko's mother

She was very much in love with Gendou.

She commited suicide after she strangled Rei who led her to realise that she was only being used by Gendou all along.

Gendou is the father of Shinji, he is the commander of the secret agency NERV. His old surname was Rokubungi he changed his surname when he married his wife Yui.
At first it seems he cares nothing for his son, but at the very end we see how similar both Gendou and Shinji are, they are both running away from those who love them because of thing that happened in there lifes, the death of his wife in Gendou's, and the rejection of his father in Shinji's.
This might not mean anything but since the death of Yui, Gendou wears glasses now, why this is i don't know.

Yui is the mother of Shinji. she worked for NERV, She was involved in an accident one day trying to synchronization with EVA 01, something that Gendou never forgave himself for, and is the reason why Gendou keeps on clinging onto the importance of Unit 01.

Her soul remains inside the Evangelion. Yui's DNA was used to create Rei which is the reason for their similarity.

Fuyutsuki is the sub-commander and second only to Gendou. The deputy commander of the secret agency NERV. Before the Second Impact, he taught in the University of Kyoto as the professor of Meta-Biology.
It is at the same place that he got to know Ikari Yui and Rokubungi Gendou.
Even shortly after the Second Impact, he was in opposition to Gendou.
However, after their meeting at the Research Institute for Artificial Evolution, he suddenly changed and started to help Gendou.
It also seemsthat he holds not just a little good feeling towards Ikari Yui.

Maya is Ritsuko's protege.

She is one of the three main Nerv operators working under Misato.

PenPen is the penguin that lives in Misato's refrigerator. Misato gave Horaki Hikar, penpen to look after.
He is a tropical penguin, and has his own quarters in the fridge and enjoys his days in the bathtub.
Pen Pen is cute but doesn't play a major role in the series.

Nagisa is 15 years old. He was sent to NERV as a replacement for Asuka when she became unable to control EVA-02 anymore.
Kaworu becomes a good friend of Shinji, who opens his heart to Kaworu. As NERV investigates, they discover that Kaworu is the 17th Angel.
As it becomes clear to Shinji that Kaworu is an Angel, Kaworu tells Shinji to kill him to let humanity live on, after a long wait he does it.
This traumatic experience still remains in Shinji's heart.

Horaki is 14 years old and a classmate of Shinji. She seems to like Touji, cooks his lunch for him the day he become pilot for EVA 04, he never did get to eat it.

Her personality changes, as she learns with Asuka and becomes more serious.