sejuani, lee sin, jarvan or volibear

Urgot.

Depends what you want from them, really.

Sejuani is a Late-Game heavy AP bruiser with absolutely brutal ganks when played right, and her ability to punish is pretty damn heavy too. She works just as well full-tank too though, and that's the current Sejuani Meta. Out of the champs listed, she's the best team-fighter and definitely has the most/strongest CC.

Lee Sin is an all-rounder with very good ganks, particularly post-6, and has powerful mobility to boot. Build him AD, and he'll dish out good damage, build him AP and people will call you a troll while you shield them for pretty large amounts, built him tanky and... Well, you'll be a tank. While people say he's hard to play, that kinda isn't true. He's easy to play, the part that's hard is mastering him. Out of the champs on the list, he probably has most potential for plays, but also needs the most mechanical skill.

Jarvan is an AD Bruiser with some hefty damages and great ganks, especially against immobile champs. Even more so after 6. He's prone to "Helping" though, which can be a bit frustrating to everyone but the enemy, but is great when played right, kinda like Lee. Out of these champs, Jarvan probably has the most reliable mobility skill, extra useful considering it also has very good CC attached as well.

And last: Volibear. I don't know THAT much about him, but he's a tank with the ability to deal damage. Basically a better Garen that doesn't spin and is actually threatening in larger fights. Nice ganks that synergize very well with short range laners, and Yasuo. ... Oh wait. Literally all of these champions synergize with Yasuo, they all have knock-ups. My bad.

But anyway, that's the basic gist of these champs. I'm being vague as the only one I know much about here is Sejuani, but I think these are accurate descriptions about what each of the champs are about. I hope it helps you pick one you like, the game is meant to be fun after all! If you want to know more specific details though, feel free to ask. I wont guarantee I'll know the answer, but It's worth a shot, isn't it? Besides, even if I don't know, someone else who does might reply as well.

... Oh. I think this thread might be in the wrong section too, by the way. I should be in Tips & Tricks I think, or maybe General Discussion.

Jarvan or.. Lee Sin.