What is Jax's Defining feature in his kit?

I think that's kind of a hard question. I think his overall identity is "gotta attack faster" and beating the crap out of people faster and faster. His Q is signature, but his W is where he draws power. His E is a husk of what his dodge used to be. And the THWUMP of his ult's passive is all to familar from getting beat up in top lane ;-;

When I see name "Jax", I think of huge damage, attack speed and counter strike. Also I think of cybernetic arms.

kinda all of it...if he wouldn´t be mobile with single-target dmg + counterstrike he just wouldn´t be jax. It´s not really a single ability that defines him, but all of them together.

http://youtu.be/CMJo3vaijx4?t=2m5s <-Jax in a nutshell for me.

Jax "Ace" feature i guess even above his dodge is that ability to deal a magic damage burst every few attacks. Its because hes primarily an AD duelist but having that magic damage burst makes him harder to tank against. And Second would be that dodge.

I can't think of anything in his kit that doesn't define him.

The thing(s) that defines him most for certain is his passives + W being used to throttle the shit out of someone though. Whap, whap, WHUMP, whap whap WOMP whap whap-

i think the thing that make jax so unique is how his kit synergies so well with his play style and lore. his passive makes it so he can get more auto attacks in which compliments his W , E , and R. His Q makes it so he can close the gap to secure kills with his kit, and to jump away when things start to look hazy. His W adds that mixed damage making it hard to armor up against, securing himself as one of the best duelist. also his W is auto attack reset so more attacks in a lesser time. his E makes it possible to make extended trades with your opponent and you coming out on top. Then his R makes his damage more consistent and his ability to engage into a 2v2 better. so i guess its just his kit that makes him unique because he is able to burst and sustain at the same time, making him truly the grandmaster of arms.

I think Jax's hybrid nature is his uniqueness.

Yes, he can be built AD to great effect, but he can also be terrifying with 700 AP as well. Even when he builds AD, the magic damage still hurts, and vice versa.

Jax is the only one in the game who can 'dodge' basic attacks and deal damage(bonus damage for more attacks dodged.)