Undying + Vengeful Spirit

Why this works

Picking these two together commits your team to an aggressive, fight-heavy game plan from the very start. Vengeful Spirit's Wave of Terror shreds enemy armor, making every zombie from Undying's Tombstone hit significantly harder. Her Vengeance Aura then boosts the attack damage of Undying and all his summons, turning a simple Tombstone into a huge source of physical damage that opponents can't ignore. A single stun from Magic Missile is often enough time for the zombies to swarm and overwhelm a target, creating a lane that's almost impossible to contest.

This early pressure allows the duo to take objectives and control the map. Vengeful Spirit can use Nether Swap to save an overextended Undying or, more dangerously, to pull a key enemy hero directly into the zombie pit. Opponents are forced to draft heroes with strong area-of-effect spells to deal with the constant Tombstone pushes. If they can't manage the zombies and survive the minus armor, this duo will simply run at them, take their towers, and build a lead that's difficult to come back from.