Lain Iwakura

Lain Iwakura (岩倉 玲音 ) is the titular character of Serial Experiments Lain.

She is a sentient computer program designed to sever the barrier between the material world and the wired, introduced as a shy Japanese girl in middle school at the beginning of the series.

Story
After receiving an e-mail from Chisa Yomoda who had committed suicide, Lain discovers the virtual world of The Wired. Throughout the series, Lain is subjected to hallucinations by the Knights in order to make her lose her sense of self and attempt to find solace in the Wired, in order to fulfill the Knights' prophecy of the arrival of the goddess of the Wired.

Personality
Lain is quiet and doesn't talk much, which leads to her being a bit of a social outcast. Her eyes are soft and naive and her posture is slumped depicting her introvert personality. She often hallucinates and sees things that aren’t real. At one point she thinks steam is coming out of her hands, in an interview director Chiaki J. Konaka said that this means that she's mentally ill.

Lain of the Wired
One time called the "Wild Lain" by Taro. It's a different Lain's persona that appears most of the time when Lain is investigating the Wired. She is no longer the introvert girl that she is usually is, she has an offensive attitude, an erect posture and she is all wide-eyed and alert. She exudes self-confidence and thrives on facts over emotion.

The Third Lain
Appearing in the fifth and the eighth episodes. Her half-lidded eyes and casual posture is demonstrating a new Lain's persona more lay back. As she only appears to torment Alice and Mika in the series, she is shown as a more vicious, ill-intentioned persona than the other. Some clues in the series may let think that she was her own entity created by the Knights to cut from the original Lain anything that could make her want to stay in the real world.

The Fourth Lain
Appearing in the final episode. It's not clear if she is another Lain's persona or her own entity. She appears more serene than the other personas. She is confident about what she knows and she is playing the guide trying to convince Lain to embrace her god nature.

Alice
Alice is the first to attempt to help Lain socialise by taking her to a nightclub, and from this point always tries to protect and take care of her.

Chisa
Chisa went to the same school as Lain and both are in the same class level. After her suicide, Chisa sent mail to all her school including Lain. Lain responded to the mail and started to chat with Chisa about the Wired. This chat launched Lain's interest to the Wired. After the chat, Chisa appeared to Lain two times but disappeared each time before having a conversation with her.

Mika
At first, Mika seems to be judgmental and rude toward her younger sister, Lain. After a while Mika seems to care and show more interest and became obsessed, leading to her downfall of later on losing her sanity.

Trivia

 * She was designed to look like her Japanese voice actress Kaori Shimizu.