For reference, that "illegal stuff" were just fireworks (too powerful, I guess) [0]. Those "attacks" are fully explained in his recent book "Hijacking Bitcoin: The Hidden History of BTC" [1]. He didn't fork Bitcoin, he just proposed its name: Bitcoin Cash [2], which is not "bcash" [2][3].

[0] https://en.wikipedia.org/wiki/Roger_Ver [1] https://www.hijackingbitcoin.com/ [2] https://en.wikipedia.org/wiki/Bitcoin_Cash [3] https://medium.com/@jonaldfyookball/why-some-people-call-bit...