SPOILERS below : Spoiler details follow
Personality, and her role in the game/anime
Also known as Mayushi☆, a 2nd year high school student currently studying at Kasensou Private Prepatory Academy, Ochanomizu. Mayuri Shiina is a childhood friend of Rintarou Okabe, which she affectionally calls him Okarin. Prior to the main story, she began working in May Queen+Nyan-Nyan as a part time maid waitress 3 months ago, and befriended Faris Nyan Nyan, the famous maid waitress of Akihabara. She is also an otaku, heavily interested in cosplay, doujinshis, and anime goods. Personality wise, Mayuri is friendly, cheerful and well liked by all the people around her, although she is also dense, simple minded and naive. However, while not the brightest character out of all, her observational skills can be sharp, beating even Kurisu Makise; she is also a good mood maker of the group, seen when she is trying to stop Suzuha Amane and Kurisu from fighting.
The second lab member of after Okarin, Mayuri claims the reason of being a lab member to be "kidnapped by Okarin's as a hostage". Although this is just a fluke used by Okarin to cheer her up when she was extremely depressed during her grandmother's funeral. Although a lab member, she is never seen participating in any experiments, due to her weakness in mathematics in general.
When she was still a child, due to the influence she got from her grandmother moments before she passed away, she developed a habit where she is seen raising her hands onto the sky often, prompting Okarin to name this habit "Stardust Shake Hand" 「星屑との握手（スターダストシェイクハンド）」. She also developed her own trademark greeting, Tutturu~♪ 「トゥットゥルー♪」, used whenever she appears to greet someone (the ♪ is necessary whenever Tutturu is used).
She is also said to have the ability to conceal her own presence entirely. Since she is easily strayed away by things she find interesting, and mislead anyone to think that she disappeared without any form of contact. It is because of that Okarin named this ability, "Stalking Fadeout" 「沈黙の直帰（ストーキング・フェードアウト）」.
Mayuri is considered to be one of the tragic characters in the story, perhaps being treated the worst out of all characters. She is also the gear that drives the plot forward during the later half of the story, since majority of it revolves around her.
Difference Between Anime and the Visual Novel
There isn't much difference between the anime and the visual novel for Mayuri's character, and her role remained the same for now. However, since the anime is still airing, the details will be laid out soon after the broadcast ends.
|Birthday||February 1, 1994|
|Interests||Astronomical Observation, Sewing (for cosplay use)|
|Self Reference||Mayushi (まゆしぃ)|
|Likes||Juicy Karaage No.1、Oden, Her grandmother's pocket watch、Sewing|