So, logically, it seems safe to assume that he spent some time in Tokyo serving as a Young Boy in New Japan Pro Wrestling, helping to set up the ring, wash the veterans' ring gear, work crowd control, etc. by day, and learning the ins and outs of the wrestling business by night, particularly the values of showmanship, fear, and respect. And taking bumps, of course. You know he put a lot of time in learning how to fall properly.
Over time he rose through the ranks, pulling off that rare feat of winning over the internet fans, the general audience, and the backstage booking team. He didn't have time for politicking, but made it clear that anyone who got in his way would be taken care of quickly, politely and easily when possible, and if not, well... Always had a solid reputation with "the boys," though, and was renowned for never stabbing anyone in the back. "My mon Bats, he don't shiv."
Stiff worker, though. Super stiff worker.
The title run was inevitable is what I'm saying.