Death Prophet + Queen of Pain

Why this works

Having both heroes on one team often creates a resource problem. Queen of Pain and Death Prophet are both natural tempo-setters who want to farm aggressively and come online in the mid-game. They end up competing for the same safe lanes and jungle camps, meaning one or both will be under-farmed. Their damage is also almost entirely magical. This makes it much simpler for the enemy team to itemize, as a well-timed Pipe of Insight or a few Black King Bars can shut down your team's main source of damage.

This awkwardness shows up in fights. Queen of Pain excels at blinking in for a quick kill on a support, while Death Prophet wants to run at the enemy team for a long, sustained fight with Exorcism. The game plan becomes muddled; you lack a clear initiator or a single, focused objective. Enemies can take advantage by either forcing fights before your cores have their key items or by simply splitting up, knowing your team struggles to punish multiple targets at once and can't effectively control the whole map.