Re: Most relaxed fighters in the ring.
James Toney was the first to come to mind. It's the main reason he doesn't gas after 5 rounds, despite being in obviously subpar condition.
Floyd Mayweather is also incredibly relaxed, even when under heavy fire.
Muhammad Ali always kept his cool and was relaxed, including when fighting Frazier and being forced to the absolute limit.
Roberto Duran was always very relaxed, despite being such an intense man when fighting. He remained very collected and relaxed when going to war against bigger men like Moore and Barkely, and honestly won due to his continued relaxation after getting tagged with big, hard punches.