The guy she's suing is apparently a fanchi named 光蛍 who constantly harassed her through superchat etc, infamous enough that if you put that name in google it pops up 光蛍 マリン as a suggestion
For example you can see people referring to 101.142.131.208 as 光蛍 and him responding to it in this thread
https://egg.5ch.net/test/read.cgi/streaming/1614646446/