Gyrocopter + Shadow Fiend

Why this works

Holding enemies inside a Call Down for a big Requiem of Souls proves unreliable. The slow from Gyrocopter's ultimate isn't enough lockdown to guarantee Shadow Fiend can get his full damage off. Both heroes want to be in the middle of the fight outputting massive area damage, with Gyrocopter using Flak Cannon and Shadow Fiend landing his Shadowrazes. The problem is they don't help each other do this. Instead, they compete for the same space and often the same farm, creating a team that has a lot of damage on paper but no way to pin anyone down to actually deliver it.

This dynamic forces the rest of the team to find all the stuns and initiation. If the supports can't provide perfect setup, both cores struggle to have an impact. Gyrocopter and Shadow Fiend are both greedy heroes who need a lot of resources to hit their stride, often leading to a passive early game where the team gives up too much map control. By the time they're ready to fight, the enemy has usually figured out how to play around them, either by kiting their short-range damage or bursting one core before the other can react.