Bloodseeker + Grimstroke

Why this works

Applying Rupture to only one Soulbound enemy is usually the correct play. The tether from Grimstroke's ultimate forces the second hero to either stand still with their ally or drag them along. If they move, they trigger the Rupture damage on their partner, often killing them outright. If they choose to stand still, the pair becomes a perfect stationary target for Blood Rite and a fully charged Ink Swell stun. This creates a lockdown situation where any choice the enemy makes is the wrong one, and Bloodseeker gets a kill or a massive damage advantage.

This pressure starts the moment both heroes hit level six and defines the mid-game. Enemy supports can't play near each other, and cores have to be careful about their positioning in every fight, constantly wary of a good Soulbind. This forces teams to play separated, making them easier for Bloodseeker to hunt down individually with the vision from Thirst. The constant threat of the combo forces out early BKBs or other defensive items, which slows down the enemy's game plan and gives your team a significant tempo lead heading into the later stages.