Magnus + Vengeful Spirit

Why this works

Getting caught by a Reverse Polarity becomes much more dangerous with Vengeful Spirit on the team. Magnus pulls enemies together, creating a perfect target for Wave of Terror to reduce everyone's armor. This happens right before the Empowered cleaves start hitting, making the physical damage from Magnus and his core stick much harder than it normally would. If a key enemy survives the initial burst, Vengeful Spirit can lock them down with Magic Missile, preventing an escape or a counter-play. Her kit adds reliability and amplifies the physical damage follow-up to Magnus's setup.

The game plan is to force teamfights once Magnus gets his core initiation items. This duo wants to fight around objectives like Roshan or towers, where the enemy team is more likely to be clumped together. The opposing side has to constantly worry about their positioning, playing spread out and investing in vision to spot Magnus before he can find an opening. Often, their best bet is to try and burst Vengeful Spirit first to remove her armor reduction and follow-up stun from the fight, weakening the overall impact of the Reverse Polarity.