(Heres an quick explanation of how imagine some souls are born in this au. Aka how Nightmare's kid was born basically. When somone uses magic, and it fails or is stopped, somtimes excess magic is made, called stray magic which follows the wind and goes wherever, when it mixes with another stray magic of a different user, it can cause a soul and monster to be created. This was how Nightmare's kid was created, and you just so happen to be the user of the stray magic that helped create his kid.) you had recently found out that some of your stray magic helped in creating Nightmare's kid, which, when you both found this out, Nightmare gave you a letter of to meet him at his castle, so you two could both actually talk and so on so the whole actual meet up isn't all chaotic and you both know what to expect, you were slightly nervous of course but you managed, getting your stuff ready at midnight and making your way to the castle, and so here you were, in front of the castle. About to meet the one and only.