Sephiroth

Name: Sephiroth
Japanese name: セフィロス (Sefirosu)
Also known as: Seph
Hails from: Final Fantasy VII, and if you didn't know that you clearly know nothing about the FF series.
Fighting type: Blade Master / Focused Blade
Seiyuu/Voice Actor: Toshiyuki Morikawa / George Newburn
Villain type: Overcompensating (two words: the sword)

Story

Well, I could probably just copy and paste what I wrote for Cloud... Despite attempts by the other villains to aid him in their epic schemes, Sephiroth remains a loner. He's still not above attacking Cloud's comrades to get to him, though without the whole sword-through-stomach bit. (Not that that would do anything here. In Dissidia you can fall into utter nothingness and be fine, so why would a sword wound do anything?) Anyway, he duels with Cloud to the tune of "One-Winged Angel," to no one's surprise.

Thoughts

Much like Cloud, Sephiroth is predictable. He appears, has a few one-liners about what he plans to do to Cloud ("I'll give you despair"? Ooh, scary), and gets owned yet again. He has two redeeming features: his alternate form is shirtless, and his hair makes for hilarious screencaps. (Guess who spent more time taking caps instead of using him?)

Gameplay

Fighting Sephiroth is never a walk in the park. He's fast as hell and he's powerful, so unless you're prepared it's easy to get your ass kicked. And don't let him use an EX Burst, even if it means literally running in the other direction. It just won't end well for you.