Jon Stones' death affected a lot of things.
BOOM!
Not even bits of Jon Stones' blood were left after he self-destructed, every organic element about this powerful Pugilist died. Everything was ground to dust by the rampaging explosion, returning them to their basest elements.
It was in these remnant elements that Blade benefited.
Jon Stones' last ability before he died was a great sacrifice on his part, all his life experiences, battle experiences, and all his accumulations flowed to Blade.
Having been embroiled in the battle alongside his mentor, Blade already entered a special state of mind that prepped him for this inheritance.
Instantly after the accumulations entered his mind, Blade felt like an entirely new personality and existence was integrated into his being.
Bzzz!
His consciousness was affected as his vision flashed and changed.
Blade's consciousness woke up inside an unfamiliar body, Jon Stones' body when he was still a teenager and a Grade F Pugilist.