Probably would be the key word, and why did you go with probably? Because you, like everyone else only knows what people say about him. You yourself have not seen all 400 of his flawless victories, you've seen at most the same 10 or 12 everyone else has, against absolute nobodies. Just being established as a jiu-jitsu master doesn't make you the best MMA fighter in history. It makes you "probably" the best MMA fighter in history.