In 2017, she began to pursue a career as a streamer instead, as she was "lonely and wanted something to do".[7] Hesitant to use her real face online, she was inspired by the Japanese entertainer Kizuna AI, the first YouTuber to refer to themselves as a "virtual YouTuber"[8]—to stream with a digital avatar to conceal her identity.[7] Her username comes from the villain Sailor Iron Mouse from the manga series Sailor Moon.[9]
After discovering that there were a growing number of users referring to themselves as VTubers like Kizuna, she began to consider herself one. The Ironmouse persona was expanded into a character, which she referred to as a "bigger version of me" and being like a superhero costume;[10][11] her avatar usually takes the form of a horned demon with pink and purple hair,[7] while its backstory—influenced by her having jokingly referred to herself on-stream as such—suggests that the character is a personification of Satan itself.[7] Ironmouse's distinctive, high-pitched speaking voice is the result of a lung infection due to CVID complications which also resulted in her being on oxygen support 24/7; she has remarked that some people have refused to take her seriously because of her voice, and that some fellow streamers have been shocked to find out that it was her real voice, and not being manipulated with a voice changer.[7][12]
Amid a growth trend for streamers in general, and especially VTubers,[13][14] Ironmouse's audience on Twitch began to see increases over 2020 and 2021. The increasing revenue from her streams also allowed her to afford higher-quality health care. In turn, improvements to her condition enabled her to perform longer streams on a more regular basis.[7] In November 2020, Ironmouse was announced as one of the charter members of VShojo, a new U.S.-based agency of English-language VTubers, joining other streamers and personalities such as Nyanners and Projekt Melody.[15][16]
Ironmouse is known for her frequent collaborations with Welsh YouTuber CDawgVA; he had learned of VTubers via Gigguk—one of his colleagues on the Trash Taste podcast. After watching an Ironmouse stream on Twitch out of curiosity and finding her to be "really funny", CDawgVA brought her up during a Trash Taste episode with Hololive English member Mori Calliope as a guest. The acknowledgement led to interest from Ironmouse, who had been also been following CDawgVA's own streams. Her involvement began with a voice cameo in one of his videos, and later collaborative streams; CDawgVA described himself in an interview with Dexerto as the "straight man" to Ironmouse's "chaotic" personality, while Ironmouse has considered him "genuine".[17][18]
In February 2022, Ironmouse held a subathon event, a nonstop stream in which a countdown clock was extended whenever viewers purchased paid subscriptions or otherwise made donations to the channel.[7] The stream remained online even when she was asleep, during which other content, such as videos, and appearances by her friends and other guests, were featured.[19] Over the course of the event, which ran for a total of 31 days through March 7, 2022,[7] Ironmouse became the most-subscribed to female streamer on Twitch, and had the largest number of active subscribers of all Twitch channels at the time (although short of an overall record set by Ludwig during a similar event he held in 2021),[20][21] with nearly 172,000 subscribers in total by the end of the event.[7] Ironmouse has occasionally hosted a talk show—Speak of the Devil—which features various guests.[22]
According to data from StreamElements and Rainmaker, Ironmouse was the eighth-most watched streamer on Twitch during the month of February 2022—marking the first time that a VTuber had made their monthly top 10.[23] Discussing the event, Ironmouse felt that it was "the only time I didn't feel lonely because I felt like I had somebody there all the time. It was the least lonely I've ever felt in a long time."[7] In March 2022, she was nominated for Best VTuber at The Streamer Awards.[24]
In December 2022, she was listed among the "heroes" on the Plasma Hero website for raising awareness about CVID and encouraging viewers to donate plasma. She has also received praise for encouraging donations to The Immune Deficiency Foundation (IDF), a charitable organization which helps people suffering from conditions like hers through research and improving the quality of life of people suffering from primary immunodeficiency.[25] According to StreamsCharts, Ironmouse was the second most-watched female Twitch streamer of 2022, behind Amouranth.[26][27] In March 2023, she won Best VTuber at The Streamer Awards.[28]
In June 2023, Ironmouse held a second subathon event as a charity event, with half of all revenue from Twitch subscriptions and Bits, as well as merchandise sales during the event, being donated to the Immune Deficiency Foundation. The subathon broke her previous record of 172,000 subscribers and set a new record of 205,461 subscribers.[29]
On December 7, 2023, Ironmouse won the award for Content Creator of the Year at The Game Awards 2023, becoming the first VTuber to win in the category.[30] In February 2024, she repeated as Best VTuber and was also nominated for Streamer of the Year at The Streamer Awards.[31]
On September 10, 2024, YouTube suspended Ironmouse's VOD channel, supposedly due to copyright strikes.[32] On September 20, her main YouTube channel was also suspended; in response, she tweeted that she was "incredibly sad and shocked".[33] Both of Ironmouse's YouTube channels were later reinstated on September 23.[34] That same month, Ironmouse overtook Kai Cenat as the most-subscribed channel on Twitch, setting a new all-time record for the service on September 30.[35][36][37] Her record lasted until November 2024, when it was broken by Cenat.[38] In December 2024, Ironmouse once again won Best VTuber, and was also nominated for Best Marathon Stream and the Sapphire Award.[39][40]
Philanthropy and raising awareness
From early in her career Ironmouse has been keen on educating more people on CVID and PI. In an interview with plasma-hero she said, "At the time, I think I was so worried I didn't realize how talking about it could raise awareness; I don't make my illness the main focus of my content, but I do speak about it from time to time for education and awareness and to explain why I may not be feeling my best at times".[25] On August 4, 2021, she held a charity event for Immune Deficiency Foundation (IDF) and raised over $100k. This caused many creators like CDawgVA to follow in her footsteps and raise more money for the charity, In an interview with the Immune Deficiency Foundation, CDawgVA stated "I find that often it’s the people that we really care about who… force us to learn about stuff we’ve been ignorant about or that we’ve allowed to be ignorant about because we haven’t had to deal or be exposed to any of the ideas.", acknowledging her role in educating him about PI and the Immune Deficiency Foundation.[41] She also did a 30-day subathon in June 2023 and a 39-day subathon in September 2024, where she donated half of all the subscription income to the Immune Deficiency Foundation.[25][18][42][43]
Ironmouse also has raised a significant amount of awareness for donations and the importance of plasma. She stated in an interview with plasma-hero, "I know so many people encourage blood donation, and I want to make sure I can reach as many people as I can to tell people about living with a PI and donating plasma. I want more people to know that we are here and we need support, but I also want people to know that they are not alone."[25] She used her platform to encourage more people to donate plasma and her efforts were well received as more people started to donate plasma, as she quoted in an interview with Dexerto, "It's really nice to be able to see so many people tweet at me every time I donate plasma, which is something I never saw before, It's just really nice to see the reception that everyone has given me, and the fact that people wanna know more about it, and people wanna donate plasma, and people wanna help out because it's a rare disease, and not a lot of people know about it."[18]Her efforts for raising awareness were also well recognized by the Immune Deficiency Foundation (IDF), which earned her the "plasma hero award" on 2024 PI Conference.[41] She is also artistically involved in raising awareness. On June 12, 2024, Ironmouse released her single "Carry On," which was the ending song for the "Compromised: Life Without Immunity” documentary by the Immune Deficiency Foundation.[44]