The Quantum Realm spits Thanos and his ship out in the wrong place. Mainly, Middle-Earth circa the First Age.


Unable to leave the planet (reasons) Thanos and his forces must instead of facing the Avengers and allies, face the entire armies of every First Age Elf, Dwarf, Human, and other allies (Eagles, etc......)


What happens?

Bonus round: Thanos and his army face Morgoth/Melkor, Sauron, and all their hordes instead.