Ember Spirit + Silencer

Why this works

Global Silence makes it very safe for an Ember Spirit to commit his Fire Remnants for a kill. A silenced target can't use defensive items or escapes like Blink Dagger, letting Ember land a full combo of Sleight of Fist and Searing Chains without any trouble. Silencer's Last Word can also be used for a similar effect on a single target if the global is down, creating consistent pickoff threat. This lockdown gives Ember the window he needs to apply all his damage before the enemy can react or get help from their team.

The game plan revolves around finding isolated targets and using that ultimate to guarantee a kill for Ember Spirit, which helps control the mid-game map. The issue is that their synergy is almost entirely based on Silencer's ultimate. When it's on cooldown, the two heroes don't interact much. Ember is all about mobility and diving, while Silencer prefers to fight from a safe distance. If enemies can survive the initial burst with items like Black King Bar or by grouping up, Ember can be left stranded deep in their lines with little direct support from a backline Silencer.