Ironmouse is a Puerto Rican VTuber, singer, and Twitch streamer. Active since 2017, she served as a founding member of the U.S.-based VTuber agency VShojo from November 2020 to July 2025. In her streaming activities, Ironmouse has been a prominent advocate for common variable immunodeficiency (CVID), an immune disorder for which she has received treatment; she has promoted plasma donation, and has held fundraisers and served as a spokesperson for the Immune Deficiency Foundation. In 2024, she became the most-subscribed Twitch streamer of all time, surpassing Kai Cenat’s first record during a September 2024 subathon, before being surpassed herself by Cenat during a November 2024 subathon.
Ironmouse originally planned to pursue a career as a coloratura soprano opera singer, but was diagnosed with common variable immunodeficiency (CVID), an immune disorder that has left her largely bedridden and isolated. It has also led to a lung infection called mycobacterium avium complex as she revealed in 2021. This required her to remain isolated from others, a situation which intensified in 2020 amid the onset of the COVID-19 pandemic. In 2017, she began to pursue a career as a streamer instead, as she was “lonely and wanted something to do”. Hesitant to use her real face online, she was inspired by the Japanese entertainer Kizuna AI, the first YouTuber to refer to themself as a “virtual YouTuber” to stream with a digital avatar to conceal her identity. Her username comes from the villain Sailor Iron Mouse from the manga series Sailor Moon.
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; her avatar usually takes the form of a horned demon with pink and purple hair, 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. Ironmouse’s distinctive, high-pitched speaking voice is the result of a lung infection stemming from common variable immunodeficiency (CVID) 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.
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”.
In June 2023, Ironmouse held a 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. This subathon broke her previous record of 172,000 subscribers and set a new record of 205,488 subscribers. In December 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. In February 2024, she repeated as Best VTuber and was also nominated for Streamer of the Year at The Streamer Awards. In December 2024, Ironmouse once again won the Streamer Award for Best VTuber, and was also nominated for Best Marathon Stream and the Sapphire Award. An annual report from StreamsCharts showed that Ironmouse was the most-watched female streamer on Twitch in 2024. In August, she appeared on Rolling Stone’s list of the 25 Most Influential Creators of 2025.
