#1.       Cross was a star sans from the beginning but Nightmare took an interest in the dark past of this black and white skeleton. So he got Killer to kidnap Cross to see if he could bring Cross to the dark side

#2.       The pair were friends as children but one day Cross disappeared. Nightmare made one promise to Cross before he disappeared: Never let his bullies become prophets (meaning don't become evil.) when he saw the villainy his friend does he tried to save him from this path

#3.        Nightmare was a demon that terrorized a large village and is given a gifts by the villagers though if they didn't have anything then he killed them. He was in Heat one day and ran into a pair of siblings with only one sacrifice. Nightmare admired the skeleton who held the gift and attacked them, cross gave up his gift to Zero to save him and was forced to be Nightmare's breeding slave

#4.        Cross was was apart of a cult to summon Nightmare from his realm but he took a liking to Cross and brought the mortal to his chaotic realm

#5.         Cross was used as a cultic sacrifice to Nightmare

#6.         Cross was mentally tortured by Nightmare since he was a child. But one day he finds out that the mitral he tortured for years was his one true mate. So he kidnapped Cross from his home to be his forced mate and bride with no choice.

#7.         Nightmare was obsessed with Cross because he was the only person that would be his friend because he like to spend time with Nightmare. He hated when people talked to Cross becoming obsessed but his brother saved Cross from him. But Dream became a yandere himself and forced Cross to be his bride. Though Nightmare finds Cross and saved him treating him better than Dream

#8.         Nightmare was a god that never found love till a mortal ended up in his temple that was beautiful. So he took them to his realm to keep them to himself

#9.         Cross was a poor person on the streets till Nightmare offered him a job

#10.       Nightmare(fully grown) saw a young Cross who treated him like anyone else even though he was a monster so when Cross was of the legal age to marry he stole Cross to marry him

#11.       Cross's brother was a demon hunter that was hired to defeat Nightmare. Nightmare would kill his brother easily if Cross didn't become one of his long line of mates that becomes his wife

#12.       Cross was an omega runt that lives with no pack but one day Nightmare needed a mate and found an injured Cross and used him as a mate for the season

#13.        Nightmare was trying to take over other lands and one day takes over Cross's parents village. Once he learned of the innocent and somewhat peaceful Cross, he makes the prince his princess