Say hello to Shulk.
For many players, Shulk's first appearance is not Xenoblade Chronicles – the 2010 Wii game he actually stars in – but Super Smash Bros. for Wii U/3DS. There, Shulk can boost his abilities to become harder, better, faster, stronger. He's also the only character possessing a costume equivalent to Samus' sports bra/short-shorts combo thanks to his form-fitting boxer-briefs.
So, why does Shulk get to change his fighting abilities in a way that no one else can? To answer that, we have to go back. Way back. No, further. To the beginning of the world.