Queen of Pain + Wraith King

Why this works

Pairing Queen of Pain and Wraith King can seem disjointed, as they lack a clean, single-spell combo. Their strength lies in creating a dilemma for the enemy team. Wraith King provides a simple, reliable frontline: he walks in, stuns a key target with Wraithfire Blast, and forces the enemy to deal with him. While opponents commit spells and attention to killing his first life, Queen of Pain has total freedom. She can use Blink to find the perfect angle to unload Scream of Pain and her other spells, often on uncontested backline heroes who are preoccupied with the king.

In practice, this means the enemy has to choose the lesser of two evils during mid-game teamfights. If they focus down Wraith King, they leave themselves vulnerable to a full-power Sonic Wave from a repositioned Queen of Pain. If they try to jump on her first, they have to deal with a durable, stunning carry wailing on them the whole time. After his Reincarnation, Wraith King is ready to help clean up anyone QoP has weakened. The two heroes don't necessarily enable each other's abilities directly, but they enable each other's game plans by forcing bad decisions.