Dealing with axe

Agree with many of the above comments - any hero who is giving you problems is worth playing, it's the best way of learning how he's countered.

My advice generally is to ignore him where possible - as an initiator/tank, his job is to absorb attacks/abilities for the rest of his team, and to give them openings where they can inflict maximum damage. He doesn't actually do very much damage unless he's being attacked or you're in Culling Blade's health range.

So, stay spread out so he can't initiate effectively, and focus on the rest of his team where possible. Disable him if you have to (e.g. he's about to kill you or initiate on your team), but otherwise do your best to concentrate on where your skills/damage are most needed.

In lane, don't go head to head with him unless you've got a hero who can beat him, and try to get rid of Battle Hunger quickly to minimise it's effects - nuke a creep, last hit one, or even a deny will do the job. High health heroes generally do well against him because his damage doesn't scale.

Anti-tanks are also worth a mention - the likes of Necrolyte's Reaper's Scythe, Lifestealer and Huskar's Life Break do bad things to him (just be careful of Blade Mail, or get your magic immunity/BKB on).

You seem to forget that there is an item that pretty much does not care about Lifesteler, the name is Ghost Scepter.A smart Axe can just buy that against enemy fed carries and just make them sitting ducks for 3 seconds.

lifestealer is a bad choice agaisnt axe, as his rage does not block physical dmg from helix
and the axe normally gets very tanky via amor items + berserkers call.
this makes naix a very bad choice against axe.

i have to say this to nearly all of you:
do not try to counter a hero with another hero.
it does not work out very well.
you have to outplay that type of hero, which dosent nessecarily mean, that you have to "counterpick".

Thanks for even more help guys,
I will now go ahead and play Axe for a bit and see how people counter me, and also I just had a realisation that couldn't Outworld Devourer would be a good counter due to his pure damage which could hurt Axe

Counter-helix does go through Rage, but after early game it's not really all that effective against a strength hero like Naix. On the other side Feast and Open Wounds are very effective against Axe and allow Naix to rapidly regen from him. Rage lets you ignore his other abilities and attack him without suffering from the effects of active Blade Mail.

Outworld Devourer...kinda, his ulty is good against a fairly low int hero like that, and pure damage is good if he gets lots of armour, but if Axe gets good initiation he might be able to get him low enough to Culling Blade him.

Ghost Scepter does make Axe a pain against carries...but then again he'd be pretty near the bottom of the list for heroes to attack first as a carry.

Axe's Tankiness comes from Armor via Berserker's Call.
Naix is bad against high armor heroes (at least at the point where Axe is scary), so Naix doesn't really counter him early on. Also he has low armor himself so helix will hurt him druing the early stages. A farmed Lifestealer is not really an arguement, since most farmed carries will kill Axe.
Also the Call is one of the better disables against Naix, since it goes through Rage. With Ghost Scepter it can be a real pain in the ***. (But very few Axes build one o.O )

EDIT: Huksar is also not so good against axe during early and early midgame. huskar has not that much health early on and his armor is ****. If you jump on axe, he needs 1-2 helix proccs and culling blade will finish you off. (burning spears will still deal some nice damage to axe though)