@endoftheline Yep. This is why the theory of Rio being the Seventh Hero is so strong. The Seventh, or in this case, First Hero, showed up long before the others showed up. That meant that he had more experience than the other heroes.
Rio awakened his memories as Haruto years before the other Heroes showed up and gained experience that way. Rio has the skill necessary to use his powers. And even now he doesn't know the limits of it.
PLUS remember how when Haruto died, a magic circle appeared underneath him? which last time i checked isn't normal for earth.