Axe + Riki

Why this works

Thinking you can split up to avoid a multi-hero Berserker's Call is the first mistake. Even if Axe only catches a single target, Riki can immediately follow up with Smoke Screen on top of the call. The silenced hero is stuck uselessly attacking Axe while Riki gets guaranteed backstabs from inside the cloud. Axe provides the lockdown that Riki lacks, forcing enemies to stay grouped and making them perfect targets for his area-of-effect damage and control. It's a simple but brutal combination of abilities that compounds on itself.

This pressure comes online the moment Axe buys a Blink Dagger. From that point on, the threat of this combo forces the enemy to play defensively, invest heavily in Sentries and Dust, and stay grouped up. Their supports are drained of resources and their cores are starved of safe farm. The only way to handle it is with superior vision to see Axe coming and instant-cast mobility or saves to pull a called ally out. If they can't react before Riki drops his cloud, the fight is often decided right there.