Phantom Assassin + Undying

Why this works

Having Undying on the team often buys Phantom Assassin the time she needs to come online. He creates so much pressure in the early and mid-game by forcing fights with Tombstone and being a nuisance with Decay. While the enemy team is occupied dealing with the constant threat of zombies and a tanky frontline hero, Phantom Assassin is usually free to farm her lane and the jungle relatively undisturbed. This consistent map pressure means fewer resources are available for the enemy to organize ganks on PA, allowing her to hit her item timings and become a major threat sooner than she otherwise might.

The result is a game where your carry gets a head start, but the direct teamfight synergy isn't perfect. In big fights, Phantom Assassin wants to find a vulnerable target and burst them down, while Undying thrives in a messy, prolonged brawl where his zombies can overwhelm people. If the enemy is focused and mobile, they can kite the Tombstone and turn on PA after she uses Phantom Strike. The pairing works best when Undying's chaos creates an opening for a quick kill, but it relies more on creating a strategic advantage across the map than on a specific ability combination.