Lifestealer

Right-click opponents as much as you can on the lane for extra damage and sustain from Feast.

Orb of corrosion is great at harrassing enemies in the laning stage and works well with lifestealers spells.

Consider investing a point in Rage early on if there's a need for dispel or spell-immunity.

If the enemy has no way to cancel rage TP, be more aggresive on sides lanes and rage TP out.

Once you hit 6, you are really hard to kill and you can dispatch your support to help other lanes.

You can save an ally by Infesting it.

Lifestealer doesn't farm fast but is decent at fighting in early to mid game. Join good looking fights.

If you have gap-closing ally you can choose to Infest him to be able to get on top of opponents quickly.

Orchid, Basher and Scythe are problematic. Adjust your playstyle and itemization accordingly.

You can slow siege opponents' building by damaging it during Rage and then backing away.

Chip damage doesn't work against Lifestealer as he is able to recover with Feast. If you manage to bring him below half HP it will be hard for him to feast as he risks dying

Buy boots early against Lifestealer as he is a fast hero who often buys Venom Orb and rushes Phase Boots

Items and spells that go through spell immunity are effective against Lifestealer

When you gank Lifestealer he will Rage and teleport out on first signs of trouble. Make sure you disable him before he rages if you do not yet have a disable that goes through spell immunity

Lifestealer's main spell in fights is Rage. Play around it by disabling him or by saving heroes he is chasing

Lifestealer tends to have lots of evasion due to his level 20 talent and a Halberd purchase. Look to counter it by getting true strike items

Keep in mind that Lifestealer might be infested in the initiating hero or that he can use Infest to escape