Bounty Hunter + Magnus

Why this works

Catching the whole enemy team in a Reverse Polarity is a great setup, but Bounty Hunter struggles to contribute the right kind of damage to it. He excels at bursting a single opponent after breaking invisibility, not delivering the area-of-effect spells or attacks needed to capitalize on Magnus's ultimate. While an Empower on Bounty Hunter can add some damage and cleave to his attacks, he's rarely the best hero on the team to receive that buff. Their kits simply point in different directions: one hero wants to group the enemy for a big teamfight, the other wants to find isolated targets.

This leaves them operating on different plans for most of the game. Magnus typically needs to farm his core initiation items, while Bounty Hunter wants to be active on the map from the very beginning, disrupting lanes and securing early kills. Even when they do group up, the success of a fight after Reverse Polarity depends heavily on what your other three teammates can do. Spreading Track around after a big setup can certainly help your team's gold lead, but winning the fight in the first place feels reliant on having other heroes who can actually follow up on Magnus's lockdown.