Ember Spirit + Lifestealer

Why this works

Controlling the map becomes much easier with this pairing, often forcing opponents to stay grouped up earlier than they'd like. The core of this advantage comes from Lifestealer's ability to Infest a highly mobile ally. Ember Spirit becomes a perfect delivery system, using a Fire Remnant to cross huge distances and bring Lifestealer along for the ride. When Lifestealer emerges, he provides a slow and heavy physical damage that complements Ember's magical burst and Searing Chains, creating a lethal ganking tool from anywhere on the map.

This duo typically comes online in the mid-game, as soon as Lifestealer gets his ultimate. They'll look for pickoffs on any hero farming alone, translating those kills into tower pressure or Roshan control. The counterplay for the enemy team is to avoid splitting up and to invest heavily in vision to spot Ember Spirit's movements. Defensive items are also crucial to survive the initial surprise attack. If the target can be saved, both heroes are left committed deep in enemy territory and can be punished for the aggression.