Ember Spirit + Grimstroke

Why this works

Pairing Grimstroke with Ember Spirit seems like an obvious win on paper, but the synergy isn't as clean as it looks. While Soulbind can guarantee Searing Chains hits a second target, Ember's spell can already do that on its own. The real value comes from Grimstroke's other spells providing lockdown. An Ink Swell stun or a Phantom's Embrace silence can hold a target in place for Ember to land his full combo, but neither is instant. The combo requires good timing and coordination to execute, making it effective but not something you can rely on every single fight.

The laning stage offers little interaction, so their success depends on mid-game rotations and teamfights. A successful gank from Grimstroke can certainly set Ember Spirit up for a kill and help him snowball. In late-game fights, the duo's impact is entirely dependent on the quality of the Soulbind. If Grimstroke manages to link two high-value, squishy heroes, Ember can often clean them both up. More often, though, enemies will play spread out, forcing a suboptimal Soulbind on a tanky frontliner, which doesn't give Ember the explosive follow-up he's looking for.