I think it's time to admit that Jax is over powered. What are his weaknesses? I can't think of any.
You can't call him melee because he has a spammable gap closer making him pretty much a ranged champ. He's tanky as hell to the point of being unkillable. And he has top tier damage output, which is consistent damage that does not have a long cool down or high mana cost.
What counters a Jax, especially an end game fully build Jax? Nothing does.
please don't be a retard like most people were about jax. see what your problem is, you ignore the fact its jax. the duelist. people like your dumbass, try and 1v1 him and call him op when he technically isn't that op. pretty simple really to beat a jax. here, ill teach you as a jax main. ward. gang up on him. dont be stupid. gg.
Jax is a hypercarry, his early game is a lot weaker, the items he builds tend to be on the expensive side so denying him CS should be a priority, pick a lane bully and you should be able to force him out of lane or kill him early on to deny levels and gold. If you want specific picks to counter him then Jayce deals with him pretty well, he can harass him in cannon form whenever he tries to CS, and can swap to hammer form to knock him away and deny the stun as well as the follow up damage, just don't swap forms for no reason since it creates a window where a good Jax can punish you. Fiora is somewhat even with Jax, she is auto attack based so his E can deny some damage, but she can also W to stun him and turn trades in her favor, she will outsustain Jax in both health and mana, and her early trades hit him pretty hard. Renekton is probably the best lane bully to pick vs him, he can dash to avoid stuns or stick to you, sustains incredibly well, and deals great early damage. Aside from that you could pick any of the juggernauts, they have strong enough early games to shut jax down hard.
Top is just a total clusterfuck right now.
Guinsoos + decent play = GG
Builds straight tank and still outdamages any non-dps class, with no cooldowns on anything, including ult.
Stupid damage and bulk for no reason, plus a heal and pentakill giving ult
1v5s if they stand in her ult.
No need for interaction
Jax is fine.
Rageblade is the issue.
I just played another game vs Jax. I ganked him several times so he was way behind. We were ahead in kills and objectives. Mid game Jax would go top and try to back door. If we sent two people to kill him, he'd kill both of them easily so we had to send at least 3 or full team, but then he'd run off and recall and we'd lose bot towers or dragon. We ended up losing because Jax became unkillable endgame. Funny how only one person needs to be caught out of position for the Jax to capitalize, but the Jax can do what ever he wants without consequence.
