Axe + Spectre

Why this works

An Axe landing a multi-hero Berserker's Call creates the perfect window for Spectre to act. He groups the enemy team together and forces them to attack him, and Spectre can immediately follow up with Haunt to have an illusion on every target. While Axe holds key enemies in place, Spectre is free to pick her target, often a fragile support, and swap in to secure the kill. The chaos Axe creates makes it very difficult for the enemy team to coordinate a response and focus down the real Spectre when she appears.

This combo lets the team play aggressively in the mid-game, a time when Spectre is normally weakest. Axe can hunt for pickoffs or force teamfights, and Spectre can join from anywhere on the map without interrupting her farm. A successful Call from Axe almost guarantees kills for Spectre, which accelerates her item progression significantly. The opposing team is stuck; if they group up to survive Axe's initiation, they set up a devastating Haunt. If they split up, they become easier targets for Axe to pick off one by one.