If we're doing this at the peak of DC's fame, I think they might win.
(The Sephy fans won't be as physically fit as the hyper 13 year olds.)
The DC Fangirls will let out a shrill cry, destroying the very beings of the Sephiroth Fans
The old men of DC will use their Liscenced(?) fire arms to gun down their foes
The Geeks will hold a ritual, offering a Virgin, to summon their hero to destroy all who oppose them
The Yaio Fangirls will simply show the DC fans their art and blind them, making them easy targets
They shall all fall in a battle royal
They all agree to create a Mural made of DCxSeph pics.
If we're doing this at the peak of DC's fame, I think they might win.
(The Sephy fans won't be as physically fit as the hyper 13 year olds.)