Around the time when Joker came out in Smash Ultimate (or maybe it was earlier - I'm not clear on the timeline), people found the codename "brave" in the files. (each DLC character has a codename, like Steve being "pickel" or Terry being "dolly" - they've been much more careful about leaving them in ever since Hero was leaked thanks to those codenames, so we don't find out what the codenames are until after the character comes out)
People almost immediately figured out that it was referring to a Dragon Quest hero (the default hero class is known as "yuusha", which means "brave" in Japanese from what I've been told), but some people tried to claim that it tied into Banjo, Agumon, or pretty much any fictional hero (bravery's a pretty common attribute) instead.