Alice Mizuki 瑞城 ありす (Mizuki Arisu)
Alice is the classmate who actually cares about Lain. She drags her to Cyberia, checks on her and keeps treating her as a friend while the others find her strange. Konaka says Alice and her friends were meant as minor supporting players borrowed from his earlier game Alice in Cyberland, and that he did not add her until late in the writing. Her part kept growing until, to his own surprise, she played a role close to Carroll's Alice, and he says he deliberately shifted the audience's sympathy toward her in the second half while keeping the camera on Lain. In an AX 2001 email interview he traced Alice, Reika and Juri back further, to a 1994 live-action school ghost-story episode he wrote. Her voice actress, Yoko Asada, also voiced Alice in Alice in Cyberland. Lain treats Alice as the one person who knew her before the Wired connected her to everyone.
More (spoilers)
In Layer 08 a rumor spreads through the Wired that Alice is in love with a teacher, and a cruel version of Lain taunts her in her own room. Lain erases the rumor from everyone's memory except Alice's. In Layers 12 and 13 Alice comes to Lain's ruined house and presses Lain's hand to her chest so she can feel a heartbeat, a case for the body that Eiri dismisses. Lain resets the world partly to spare her. Years later an adult Alice, now a student teacher with a partner, meets Lain in the street and feels they have met.
Sources: en.wikipedia.org archived · ja.wikipedia.org archived · animenewsnetwork.com archived · konaka.com archived · lawmune.net · 4gamer.net · lain.wiki · lain.wiki