Necrons

Description
The Necrons are an ancient alien race that sold their souls to the C'Tan Gods in hopes to save their entire race from dying. The deal ended horribly and they were stripped of their souls to be eaten by the evil gods they made a deal with. The aliens minds were placed in body of machinery converted as warrior slaves to harvest all lifeform souls for the C'Tan and kill all life living on the planet, everything organic is purged. It then starts over when life resurfaces again as does later when the Necrons are sealed inside tombs.

The Necrons battled with the C'Tan God Overlords for control over the universe. The bad news was Evil won nearly were it not for the Necrons royal leader The Silent King who planned out a coup to destroy the remaining C'Tan alive from the war against the heavens rather than be slaves for eternity. It succeeded and the Necrons were finally freed. The Silent King ordered the Necrons hide inside tombs now that they realize the Eldar race outnumbers them. Every last one of them went to sleep save The Silent King.

He went to a long lasting exile afterwards and found out in his long search the galaxys worst nightmare. The Tyranid swarm who have killed and consumed many organic lifeforms from the planets they conquered gave no mercy to. The Silent King realizes the grave threat and warns his race to watch out for them. If they kill all organic life. The Necrons will have less hope to transferring minds to organic life.

His journey will have yet to reach the other Necrons who lay dormant inside their tombs or have turned evil lawfully to create a Necron Empire to conquer other races they despise. Either they spare them as slaves or bring them to what uses they have for them that can end badly.

Necrons wield gauss weaponry like the USNC from Halo. The only difference is the Necrons have them mass produced successfully as handheld weapons than just their vehicles and defense weapons.

Necrons possess a powerful healing factor and if they somehow get destroyed as a corpse, they can sometimes reassemble themselves fully healed. If its damaged beyond repair. The inactive bodies are transported to the underground necron tombs hidden across the galaxies even ones turned into puddles of goo.