Bloodseeker + Sniper

Why this works

Catching a key hero with Bloodseeker's Rupture creates a dilemma. The target is heavily punished for any movement, making it very difficult for them to reposition or escape. This gives Sniper a much cleaner window to attack from a safe distance, as the enemy has to choose between taking Rupture damage to run away or standing still to eat Sniper's shots. If they get low, Bloodseeker's Thirst grants vision, setting up an easy Assassinate for Sniper to finish the kill from across the screen. The two abilities combine to make life very difficult for a single target caught out of position.

This synergy is strongest when your team is looking for pickoffs around the map. Bloodseeker can initiate from an aggressive angle, apply his ultimate, and fall back while Sniper provides the sustained damage. The main weakness is that it relies on finding isolated targets, and it offers little if the enemy team groups up and commits to bursting Sniper first. A team with good defensive saves, like forcible movement or invulnerability spells, can also negate the Rupture threat entirely. This makes the pairing effective in certain situations but not an automatic win, as the enemy team can adapt their playstyle and draft to counter it.