Medusa + Warlock

Why this works

Pairing a big teamfight ultimate with a hero who wants to stand her ground seems like a clear win. Warlock can create a huge chaotic area with his Golem, and linking enemies with Fatal Bonds lets Medusa’s Split Shot do massive damage. The problem is that beyond that one big moment, Warlock offers little of what Medusa needs. He doesn't have a reliable stun to hold a target down for her, nor a strong defensive save to bail her out if she gets jumped. Upheaval is a powerful slow, but it forces Warlock to channel, making him an easy target and unable to use other spells.

The game plan becomes very predictable: wait for Chaotic Offering, then try to win one decisive fight. When that ultimate is on cooldown, the enemy team has a huge window to act. They can split the map, pick off Warlock, or coordinate a gank on Medusa, knowing her primary teamfight support is unavailable. She is often forced to play defensively and can't use her mid-game strength to secure objectives. While the combination can work if the stars align for one perfect ultimate, it often leaves Medusa feeling unprotected between those big cooldowns.