Reira Serizawa's actual birth name is Layla--she was born to a Japanese mother and an American father. Layla's friendship with her band comes all the way back to her elementary school days, starting with Takumi Ichinose. The two met when Layla and her mother moved to Japan. Often criticized by the neighborhood because of her then-vague understanding of the Japanese language, Takumi was asked to befriend her. The two stuck together throughout their childhood, mostly teaching each other about their first language - Reira learned more about Japanese, while Takumi learned more about English.
Layla always showed an interest in singing at a young age, seen through her rendition of Cyndi Lauper's "Time After Time". During one of the first times she's shown singing this, she tells Takumi she loves him and gives a rather unexpected kiss. As this prompts him to be (not unexpectedly) put-off, Layla explains, though not very convincingly, that she often kissed (or was kissed by) anyone she respected or admired back in America, such as her parents or teacher. After being told that it's usually only reserved for "adults in love", Takumi reluctantly tells her it's fine if she does that, or holds hands with him, as long as it's only when they are alone.
Their friendship remains a close one until the beginning of middle/junior high school, when Layla (again) kisses him after he calls her cute, just like any other day. This time, however, he admits to her that they're getting older and she should only do those things with a boyfriend. Layla doesn't hesitate to ask him to take that place, but Takumi, somewhat unwittingly, rejects her coldly, saying he already has a girl of his own. Takumi begins to tell Layla it shouldn't be hard for her to find a nice boy herself, but by then she's gone from the room.
In between junior high and high school, she befriends both Naoki Fujieda and Yasushi Takagi, the latter of which was then in the band Brute with Ren Honjo. Layla became frustrated with Takumi only seeing their relationship as that of a brother and sister, or in her eyes, being nothing more than Takumi's "caged songbird". At one point in time, she even asks him what she is to him, but he doesn't respond. To deal with her unrequited feelings, she begins to date Yasu. Their relationship doesn't last, but it was a nice distraction from the pain.
Within Trapnest, she has at times been seen 'expressing' interest in both Takumi and Ren, drawing the ire of Nana Osaki. To make matters worse, the tabloid magazine, SEARCH mailed to Nana photographs of Ren and Layla together, though the shots were simply of an innocent trip the two took to their hometown. To stop the magazine from publishing the photos, Takumi decided to reveal his relationship with Hachi, who initially was suspicious of Layla as well.
Around the time when her band was at its most popular, Layla decided to visit a nightclub in an attempt to pick up an escort for the night. In doing this, she meets and provokes the attention of Shinichi Okazaki. After spending a night with him, she continues their meetings. The two eventually decide (at first through Layla's wishes) that the relationship is more than that of a prostitute and client, and Shin requests she no longer pays him to stay the night.
Eventually, Takumi catches onto their situation. Knowing that the teen was underage, and also that Layla could possibly ruin her career, Takumi warned both parties to think of the possible consequences. Layla initially brushed off his idea, later realizing how potentially dangerous their meetings were, thanks to the media's recent capture of Layla and Ren together. She reluctantly breaks it off with Shin, only to regret it and beg for forgiveness, possibly repairing their relationship. Shin, however, still a bit scared of Takumi's warning and not wanting to sully her reputation, refused. The two have yet to get back together.