As soon as he said "mate" I would've blocked and removed him immediately. I am not your mate. We are not mating.
Other than that he seems perfectly levelheaded and reasonable. What's his jsp? ^ him here.
That ones on me, someone calling you mate in d2 is the biggest red flag.
But yeah hes one of the most humble and respected OG's out there, everybody in the duel community knows him. He is basically the GM raid boss.