She eventually became Lab Mem 005, joining in episode 6. Moeka joined because Okarin didn’t want her to leak the PhoneWave secret.
Moeka was a constantly bullied social outcast, she desperately tried to make friends and find a place to belong, but failed miserably due to her social paranoia. In 2004, she fell into a deep depression due to hating everything and being hopeless, thinking that she no longer had a reason to live, Moeka decided to commit suicide. She drank several sleeping pills, hoping that she would die, but to no avail. As the pills were not working, her final attempt was to jump off a large building. At that moment, she received a mail from the enigmatic FB recruiting her to the Rounders, a SERN unit, changing her life forever. As FB often communicated with Moeka and acted as a mother-figure towards her, speaking with Moeka about her problems and comforting her, she came to see FB as the person that gave her life meaning and devoted every waking moment to sending mails to them and carrying out their given orders, developing a dependency on FB and their mails. While Moeka is capable of carrying out atrocities for acceptance’s sake, she strives to be loved and has the potential to be a good person if led in the right direction.
In episode 12, she kills Mayuri at FB’s order. However, Moeka was just a fate tool on that subject, since Mayuri is fated to die on the Alpha Attractor Field due to Okarin’s D-Mails.
In the visual novel, Okarin and Moeka confront Yuugo about the IBN5100, he later reveals to them that he is FB and that FB is the initials of Ferdinand Braun. Pulling a gun on Moeka, Yuugo admitted that he was FB, pretending to be a woman to appeal to Moeka’s insecurity; he also informs the two that Rounders who complete their missions are killed by him. Okarin proceeds to reveal the truth about Hashida Suzu, the woman who took care of Yuugo and became a mother figure to him. After he found out the relation Hashida Suzu had to the time machine and the future, he regretted his actions, and committed suicide to protect Nae and Moeka, as he wanted to save the latter. His death caused Nae to become vengeful, especially against Okarin and Moeka. She later became the Rounder commander, and killed Okarin in 2025, then time-leaped 15,000 times back to the time of Moeka’s death to kill her and warn Okarin of his death. As Moeka dies, she apologized to Okarin for Mayuri’s death. Believing that her death is her punishment for killing Mayuri and that Okarin is right to hate her, as she would kill to protect the place she belongs. (FB’s affection and care towards her) Reminding himself that Moeka did not kill Mayuri in this timeline, Okarin forgives Moeka as she dies.
In episode 20 of the anime, she discovers that FB is Tennouji Yuugo, and that he was manipulating her to find an IBN5100. She’s later shot by him and remembers that she killed Mayuri on various time lines. As Moeka dies, she repeatedly apologized to Okarin for Mayuri’s death.
In the Gamma world line, Moeka is saved by Okarin and he recruited her to the Rounders. She considers him and FB her family and, though not realising, harbors feeling towards Okarin.
She can talk normally on this world line, but she still has some difficulties.