Nidavellir

Nidavellir is a made-up word. Yeah, we know, Thor. ALL words are made up. Originally known as Niðavellir, it is a location featured in Norse mythology. It is the home of a race of Dwarves related to the kingdom of Asgard. It relates to Skáldskaparmál - the second part of the Prose Edda by Snorri Sturluson. In film fiction, it is the name of a star as well as its sole orbiting body featured in the Marvel Cinematic Universe. It appeared in the 2018 film Avengers: Infinity War.

History
Nidavellir is a neutron star and part of the Nine Realms of Asgard. It is orbited by a multi-ringed megastructure occupied by a race of Asgardian dwarves. This structure houses a great forge, which gained legendary status for manufacturing the most powerful and horrific weapons to ever torment the universe. Thor Odinson's enchanted war hammer, Mjolnir, was forged at Nidavellir.

The Mad Titan known as Thanos came to Nidavellir, demanding the dwarves to forge him a powerful gauntlet that was strong enough to contain the energy of the six Infinity Stones. After construction of the gauntlet was completed, Thanos massacred all 299 dwarfs living on the structure, sparing only one, Eitri, though Eitri did lose the use of his hands during the encounter.

A short time later, Thor, having lost Mjolnir to the destructive power of his half-sister Hela, journeyed to Nidavellir with two companions, Rocket and Groot, in the hopes of convincing the Dwarves to make him a new weapon. They found only Eitri, whose hands had been smelted into metal prosthetics. Thor urged Eitri to craft him a new weapon. Eitri re-ignited the star to power his forge. With Thor's assistance, he forged a new head for a weapon, which was affixed to a limb taken from Groot for its handle. This weapon became known as Stormbreaker. Armed with this new device, Thor left Nidavellir to bring the fight to Thanos on Earth.

Residents

 * Dwarves (299)
 * Eitri

Marvel Cinematic Universe

 * Avengers: Infinity War