Doom + Void Spirit

Why this works

Catching a hero with both Doom and Void Spirit feels like a guaranteed kill, but it’s often an inefficient one. Doom’s ultimate already takes a single enemy completely out of a fight for a long time, disabling their spells and items while dealing heavy damage. Void Spirit is also built to isolate and burst down a single target with his spell combo. When Void Spirit unloads everything on a Doomed target, it’s usually overkill. That hero was already neutralized, so you're spending a full set of burst spells on a target who can't fight back anyway.

Across a game, this pattern means you’re frequently committing two of your most important cooldowns to kill one enemy. While effective for that pickoff, it can leave the rest of your team exposed in the ensuing fight. A better partner for Doom might offer AoE control or sustained damage for the rest of the enemy team, while a better partner for Void Spirit might provide a stun that lets him land Aether Remnant on multiple heroes. These two heroes are both lone hunters who do similar jobs, so they end up competing more than they cooperate.