Enigma + Faceless Void

Why this works

Stacking two massive teamfight ultimates often seems like a guaranteed win, but the reality is more complicated. Chronosphere freezes everything inside it, including Enigma's Eidolons and any Midnight Pulse damage. This means if Faceless Void goes first, Enigma can't contribute his own damage to the targets inside and might even get caught himself. If Enigma lands a good Black Hole first, a follow-up Chronosphere is usually overkill, trapping heroes who are already disabled. The two abilities serve a similar purpose but actively interfere with each other, forcing a choice between them rather than allowing them to build on one another.

This leads to awkward teamfights where one hero has to hold their biggest spell. Enigma might be waiting for the perfect five-man Black Hole while Faceless Void needs to use Chronosphere to kill a single priority target. Because both heroes depend so heavily on these long-cooldown abilities to be effective, having them on the same team makes your strategy predictable and inflexible. If the enemy team has good saves or can force fights while one ultimate is down, your entire game plan can crumble. The combo relies on perfect, often impractical, scenarios to work as intended.