Mr Peter, former champion- If Peter is his first name and not his family name, I wouldn't use Mr- use that with the family name of when using both names. Also there's an article missing: a/the former champion, depending ion how great he was, and how many other champions there are. There's another missing article in the same sentence.
moveset- where did you find this? Onelook searches hundreds of dictionaries and none have it.
brawling- this suggests drunks fighting in a bar rather than professionals, especially with his good moves. In British English, people sometimes use 'grapple' in this context.
with other colleague- Plural?
before becoming - This doesn't sound right because the subject it 'it' not the wrestler, so I'd use 'before he becomes'.