Beastmaster + Grimstroke

Why this works

Facing a Soulbind on your team often means a Primal Roar is coming right after. The double stun from that combo is a great way to lock down two heroes and start a fight with a huge advantage. The theory is sound, but this pairing leans almost entirely on that single interaction. Outside of that big ultimate combo, Beastmaster's kit doesn't have much to layer with Grimstroke's spells. Beastmaster's damage is mostly physical and sustained through his summons, which doesn't get much of a boost from Grimstroke's magical damage or slows.

This dynamic means the duo has a powerful but infrequent gank threat. If the Soulbind-Roar play doesn't secure a kill or a major objective, both heroes have long cooldowns and less impact. Beastmaster often wants to use his summons to apply pressure to towers and split the map, while Grimstroke needs to be with other allies to set up kills. This can lead to them playing apart from each other, making it hard to find the right moment for their one big play, and leaving the rest of their teamfight contributions feeling a bit disconnected.