Naix The Lifestealer is a good late game strength carry that activly counters any other strength hero by just ripping through their life points with his fiest abilitiy
This is basicly a free five second BKB that also increases your attack speed which is very good for Naix because of his passive ability
This is what make Naix such a good counter to other strength carrys the 7% damage maeans hitting targets with higher hp will make you do more damage and keep you alive longer
This is Naix's only CC helping you chase down fleeing enemies and will give your allies that are attacking that target lifesteal we max rage over this however because the slow on this ability does not get better as you level up but the cooldown does decrease significantly
This ability can be used in two ways. You could use it to heal yourself up a bit in teamfights if you get low by infesting a creep if there is one around or you can use it on your initiator to get you in the teamfight right away and add a little punch to their initiation.
Get the stout sheild and quelling blade so you can kill the creeps faster and take their hits easyer and the tangos so you can keep your life a little bit higher early on in case the enemy trys to kill you in your jungle
Power treads are the best boots for Naix because the attack speed is amazing for him plus the pure stats it gives. Armlet is the most important item for naix because his passive lifesteal negates its damage over time on you and it will give him again more attack speed, damage, and HP. Midas is a good pick up as your first item if you can get it within the first eight minutes but if your going to get it you will have to commit yourself to farming.
These are two very good mid-late game items for naix mjollnir because again more attack speed and some pushing power. Skull basher is good because naix has no disables so people getting away from him is a common problem and this can help stop that.
MKB is a good choice if you are going against an agility hero with butterfly or if you just wanna hit harder. Halberd can help you if your against a hard right hitter and you need some more CC for him. Heart will give you some overall survivability and damage. BKB is good if you dont think your 5 seconds of magic immunity from rage is not enough and with this if used right you could have a minimum of 15 seconds of magic immunity. Abyssal is good if you are going against someone you need stuns for who has a BKB and it will give you in general more damage
You want to start out by killing the small camp twice at the start so killing it after the 30 second spawn then going out of blocking range then killing it again for an easy level two then killing the medium and small camps until level 3 or 4 at that point just go through every camp every time they spawn.
Naix is more of a pubstomp hero he is not picked up much in the professional scene.