Shadow Fiend + Phoenix

Why this works

Setting up a big combo with Requiem of Souls and Supernova seems straightforward, but it's often awkward in practice. For his ultimate to do significant damage, Shadow Fiend needs to be right on top of his targets. Phoenix, however, often uses Supernova at the end of a long Icarus Dive, deep in enemy territory. This forces Shadow Fiend to either commit to a dangerous position alongside Phoenix before the fight is controlled or arrive too late. The coordination required to have both heroes in the perfect spot at the same time is difficult to achieve.

Throughout a game, this pairing relies on one big, telegraphed play. Enemies will see the draft and know to save escape tools or a Black King Bar for the moment Phoenix dives. They can focus on bursting the Supernova egg quickly or simply spread out, giving Shadow Fiend no good target for his ultimate. A successful combo can certainly turn a fight, but more often, one of the two heroes uses their ultimate for their own survival, breaking the synergy and leaving the team waiting on long cooldowns for the next attempt.