(Actually Shadow wasn't stolen, we just picked it out. There was also a ninja in FF3 called shadow I do belive, but it's not a ripoff of that either. I KNOW BECAUSE I WAS THERE, HELPING~ The allusion is still apt though, so keep it.)
Well, they seem to be on equal IQ footing, so it's not about one outsmarting the other, Shadow's speed is huge, and if his energy projection were at all decent, I'd say he'd win by never being touched. Unfortunately with such lack of range, it'll turn into a melee fight. It's close, very close, because shadow may be able to fight the whole time without having a single blow landed on him with such huge speeds, but fyber can be hit a few times while he only has to make one good swipe to knock Shadow over. GOD I WANT TO SAY TIE.
However, I'm going to give it to Shadow, based purely on superspeed versus fyber's rather "playing the board" stats.