{ The groom of shadows } canon x oc

the star sanses having been battling the bad guys (dark sanses) for many years have finally been able to defeat them, or so they thought... 3 years later as past and one of the member (oc Arrow) as a feeling that it is not over between the bad guys and that they are still lurking. In order to make him feel better, the other members throws a party for him. But unfortunately that's when Nightmare sans reveal himself and brings chaos to the land. In order for nightmare to free the AU and the entire multiverse (and dream), he asks for 3 things in return. A AU to bring upon darkness into, for others to never use their powers on him (or his crew) and a bride/groom to marry. Arrow volunteers to be his groom and gets send to nightmare's castle to be his soon to be husband.