The guy is always running everywhere without being tired.
I read an article recently about french rising athlete Jimmy Gressier where one of his prior football coach said that at 14yo they made some kind of pacer test, and that he was the only one of the team to reach the last level of 22km/h. He said that he remembers that only one other guy he coached managed to do the same and it was N'Golo Kanté, but he was around 18 yo when he did the test, and Gressier 14 yo.