Viper + Zeus

Why this works

Applying Viper's Nethertoxin to a target is the setup for Zeus's burst. That pool on the ground reduces magic resistance, making a follow-up Lightning Bolt or Thundergod's Wrath hit significantly harder. Viper's slows from Poison Attack and Viper Strike also help hold a target in place long enough for Zeus to get his spells off. The basic game plan is for Viper to corner and soften up an enemy, creating the perfect window for Zeus to unload all of his magic damage from a safe distance or even globally.

This plan often falls apart because of their shared vulnerabilities. Both Zeus and Viper are slow heroes with no real escape, making them easy targets for ganks. They also lack hard stuns, relying on slows that can be countered by mobility spells or items. If the enemy team drafts heroes that can close the distance quickly, they can often pick off both cores before the damage combo can even be executed. Without a strong frontline and other sources of lockdown from teammates, they are often left too exposed to function effectively together.