Underlord + Rubick

Why this works

Setting up a kill with this pair often involves Rubick's Telekinesis. Lifting an enemy gives Underlord a free window to place Pit of Malice and Firestorm directly underneath them, guaranteeing the root and initial damage. It's a reliable lockdown chain that works well on a single hero. Beyond that direct combo, their kits don't overlap much. Underlord wants to stand in the middle of a fight with his aura, while Rubick prefers to stay on the edges looking for a key spell to steal. They operate in different spaces, so they rarely interfere with each other's plans, but they don't dramatically boost each other either.

As the game goes on, their main shared goal is controlling teamfight space. Underlord can create a large dangerous area with his spells, and Rubick can punish anyone who gets caught or tries to flank. Fiend's Gate can also be a useful tool for repositioning Rubick to a better angle for a game-winning Spell Steal, or for bringing the whole team to a fight. However, the success of this pair depends heavily on what spells are available for Rubick to take. If the enemy lineup lacks big teamfight abilities, Rubick's impact is muted and the duo feels much less coordinated.