>>54122091NTA, but when Hololive Alternative was in production, Kei was one of the people in production to work on a manga centered on Marine.
After the trailer released, the boom in popularity was bigger than what everyone expected, so Kei decided to negotiate a higher pay. Cover declined, so he decided to fight back.
In the end, the manga got cancelled, he's no longer in speaking terms with Cover (including Marine), and he also deleted all his Hololive works and doujins to end it on a note. His manager told his fans about the events in their bilibili stream. You can probably search for the stream if you wanted to.
Shame. His works are great too. That's what happens when an immovable object meets an impending force that just won't take no for an answer.