Who the absolute fuck is Hakuoho and how did they go from literally not existing to yusho race in 6 months?

Hakuoho did sumo non-professionally and was good enough to be allowed to start midway through Makushita, Endo did something similar way back when he first appeared. He did that 4 basho ago and has been burning through all the lower competition since, clearly belongs in the top, it's just a question of where his ceiling is. Also if you couldn't already tell, Miyagino (the former Hakuho) is signaling his faith in this guy's abilities with his ring name.