Demons were the most widespread type of fiends. They were chaotic evil by nature, and were native to the Abyss.

Where do demons come from D&D?

Demons are a vile race of fiends in the roleplaying game Dungeons & Dragons. Native to the Abyss, demons are chaotic evil by nature and delight in dispensing death and destruction wherever they go.

Are there demons in 5E?

A quick list of the creatures that are covered in the 5E Monster Manual here: Balor: Huge fiend - demon; chaotic evil; CR 19. Barlgura: Large fiend - demon; chaotic evil; CR 5. Chasme: Large fiend - demon; chaotic evil; CR 6.