Slardar + Viper

Why this works

Picking these two heroes together looks like a straightforward ganking setup, but the damage types don't always align. Slardar's Corrosive Haze is one of the best physical damage amplifiers in the game. The problem is that Viper deals almost exclusively magical damage with his Poison Attack, Nethertoxin, and Viper Strike. This means the core benefit of Haze is largely lost on him. While the combination of Slardar's stun and Viper's slows makes it incredibly difficult for a single target to escape, they aren't directly boosting each other's primary damage output in a significant way.

In practice, this duo excels at picking off a single, isolated target. Slardar can initiate with a Crush, apply his ultimate, and Viper follows up to melt the hero down. This strategy works well in the mid-game to create space and secure objectives. However, it falls off against teams that stick together or have multiple defensive support items. Because both Slardar and Viper are so single-target focused, they can be overwhelmed in a full five-on-five teamfight where area damage or team-wide control is needed. Their plan is effective but predictable, and good opponents can play around it.