In early September, Eimi did the "oopsie" shown in the video. The "oopsie" was her showing her DMs with Tenma, which contained a link to a non-password protected Google Drive that contained some of Tenma's model and asset files. People quickly downloaded the files and re-uploaded them before the original Google Drive link could be taken down. Some people on Twitter and other places used the model for shitposting and other things.
In usual Phase fashion, they stayed silent on the matter, and both Tenma and Eimi streamed as normal. A few weeks passed, and suddenly, various Phase girls started doing streams using Tenma's model and pretending to be her. These included Uruka, Nasa, Iori, Dizzy, Ember, Remi, Rie, Erina, Panko, Runie, Clara, Pico, and of course, Eimi. The phrase "Tenma fever" had been thrown around a bit during this.
It all lead up to a stream three weeks after the leak on Tenma's channel titled "fever". In the opening of the stream, various people including the Phase girls above and many more people including MariMari_EN, Clio, Nyaru, Obake Pam, Lilybelle, Nagzz, Koefficient, Randon, and many more including Sakana appeared dressed as Tenma and claiming to be Tenma themselves.
At the end of her "fever" stream, the above clip took place. And afterward, there was a large collab with Tenma and many of the other Phase "Tenmas".
So what was this whole "Fever" thing about? It was her brainchild to celebrate her hitting 200k subscribers on YT and make a few announcements like a new cover and an upcoming 3.0. It seems likely that she decided to turn the initial "oopsie" to work in her favor and planned this entire thing around it. Though, some theorize that the leak may have been intentional, which while far-fetched, might be possible given the perfect timing for her reaching 200k and the time between the oopsie and Fever stream was only around three weeks meaning a lot of planning and execution had to be done in those three weeks.
Either way, the fact Tenma was able to take this yab and create such a fun event from it, and although not directly saying what Eimi did, addressing Eimi's "oopsie" and "punishing" her for it was amazing to watch. Absolute peak.