Grimstroke + Ogre Magi

Why this works

Picking these two supports together is a bet on their late-game spell potential. Grimstroke's Soulbind allows Ogre Magi's single-target abilities to hit two heroes instead of one. The real payoff comes from Ogre’s Multicast. A multicasted Fireblast on a Soulbound target can instantly stun and burst down two enemies at once, often from a surprising distance. Even a copied Ignite can add up, slowing and burning down a pair of opponents trying to disengage. It's a high-impact combination that can turn the tide of a crucial fight.

Actually landing this combo requires some setup. The enemy team will learn to play spread out to avoid Soulbind, and Ogre Magi still needs to get into casting range. Grimstroke can help with this by using Ink Swell on Ogre to close the distance. Outside of this specific ultimate interaction, their kits don't overlap in a major way, though Ogre's Bloodlust is always a welcome buff for any core. The potential to delete two heroes is always there, but its dependency on positioning and cooldowns keeps it from being a consistently dominant strategy.