Legion Commander + Spectre

Why this works

Catching an enemy with a Duel becomes a much simpler kill with a Spectre on the team. Legion Commander provides the long, single-target lockdown, and Spectre uses Haunt to instantly join the fight from anywhere. The target is held in place, letting Spectre and her illusion unload damage without any chance of escape. This turns any successful Duel into a kill with global range, meaning no enemy is truly safe while farming alone, regardless of where Spectre is on the map. The combo is reliable and doesn't depend on tricky positioning or timing windows.

This dynamic forces the enemy team to play defensively and grouped up as soon as Spectre gets her ultimate. Any hero trying to farm a lane or jungle camp alone is a potential victim for a Legion Commander blink-in. The constant threat of a global gank starves the enemy of resources and map control. For the enemy supports, saving a Dueled ally is extremely difficult because Spectre's Haunt illusions will also be distracting and damaging the rest of their team, creating chaos while the primary target melts.