Don't quote me on this. I may not be completely accurate, so feel free to correct me. I'm going to keep it short, simple and very general.
aPatroklos:
- Very fast.
- Ridiculously complicated.
Aeon:
- High damage.
- Slow.
Algol:
- Can fight at any range.
- (I don't know enough to say anything bad about him)
Astaroth:
- High damage, long range.
- Arguably the slowest character in the game.
Cervantes:
- High damage, decent range.
- (I don't know enough to say anything bad about him)
Dampierre:
- Very mysterious, not sure what he'll do next.
- Some useless moves, comical character.
Devil Jinn:
- Powerful moves, good combos.
- Must be in very close range to be effective.
Edge Master (or Elysium/Kilik):
- Knowing a combination of characters means that your opponent can't learn a strategy because your style changes in mid-fight.
- Your weakness solely depends on your knowledge and skills of the characters, and that of your opponent.
Ezio Auditore:
- CH fishing.
- Some unsafe moves.
Hilde:
- Good fighter at close/long range.
- Arguably complicated to use.
Ivy:
- Can fight well at almost any range, great unblockables.
- Long range moves are very linear and unsafe when stepped.
Leixia:
- Fast, tricky and good mix-ups.
- Short range character.
Maxi:
- Fast, decent range and good mix-ups.
- Stance transitions leaves him wide open.
Mitsurugi:
- Balanced in range, speed and power.
- Struggles against faster characters sometimes.
Natsu:
- Surprising speed and power, decent range.
- Weakness is against patient players.
Nightmare:
- Good range and power, surprisingly good speed sometimes.
- Unsafe moves and some slow attacks is his weakness.
Patroklos:
- Decent speed and power, good at punishing.
- Mostly short range moves.
Pyrrha:
- Decent speed and power, good at punishing, arguably the safest character in the game.
- Short range, familiar patterns.
Pyrrha Omega:
- Almost the same as Pyrrha, but more power and more unsafe. (As far as I know.)
Raphael:
- Great speed and range.
- Weak moves, somewhat linear.
Siegfried:
- Powerful moves, surprising speed.
- Mostly slow moves, unsafe stance transitions.
Tira:
- A decent variety of moves. (I don't know much else.)
- Her weakness is her Jolly mood.
Viola:
- Can fight at any range, extremely high pressure.
- Weakest at mid range, familiar patterns, frustrating to use because of complexity and timing.
Voldo:
- Decent range, mysterious and good at mixing up.
- Slow.
Xiba:
- Good range, good balance between horizontal and vertical moves, high damage.
- Slow, hard to punish players.
Yoshimitsu:
- Good speed, great mixups and has by far the most unblockables in the game.
- Somewhat complicated to use, unsafe moves.
ZWEI:
- Decent mix-ups.
- Slow and inconsistent.
Jared The Killer (JTK)
Edited for Edge Master.