Oracle + Slark

Why this works

Saving a low-health Slark with False Promise sounds good, but it is often redundant. Slark is an expert at keeping himself alive. He can purge stuns with Dark Pact and will quickly regenerate with his ultimate's passive as soon as he slips out of vision. Oracle's big save can feel unnecessary on a hero who already has multiple escape tools. A well-timed False Promise can extend a fight, but it isn't the same game-winning synergy it provides for less slippery cores. Both heroes are trying to solve the same problem—Slark’s survival—but their methods don't always combine effectively.

This lack of strong synergy means the pair doesn't create early-game pressure as well as others. Slark wants to be active, finding pickoffs to snowball, while Oracle is more reactive and defensive. In teamfights, the success of False Promise depends on Slark continuing to fight and lifesteal instead of instinctively disengaging. If the fight turns and he can't hit anything, the burst of tallied-up damage at the spell's end can easily kill him. Oracle is a powerful support, but his kit often overlaps with what Slark already does for himself.