Nightmare (Earth-9621)

"No one wants you more than me, Siegfried. No one cares about you. They think it is a sin for you to be alive. But I know better... That together we can accomplish the unimaginable. The realms will be ours."

- - Nightmare to Siegfried

Nightmare was the manifestation of Siegfried's corrupt symbiotic relationship with the cursed sword Soul Edge, where he roamed Earthrealm as the bloodlusted Nightmare. After Siegfried was freed from his curse with the help of the White Lotus Society, the fragments of Soul Edge escaped from Siegfried, becoming an entity without the need for a host.