So I came up with these great ideas for stories check it:
1) Sombars night: Luna and Sombar where in love before he died. This is a story about that love.
2) Alive again: Luna brings back Sombar from the dead. She hides him in the dungeon and they finally get a chance to catch up.
3)Forever night: After bringing Sombar back from the dead Luna is convinced to turn back into nightmare moon and together they will rule he night.
4)Luna loves you: Luna takes some time away from the castle to visit Sombars grave, again.

Good right? I just wanna know if they should be separate stories or on big story, what do you guys think?

I think you mean Sombra.

I'd post them as one long story. But I think it also depends a bit on how long it will take you to write them. If it's going to be months and months in between each posting, doing them as individual stories is a better idea, especially if each one comes to a good ending.

2796955

If Sombra got brought back from the dead in the third story, then why is Luna visiting his grave in the fourth one?

2816724 he dies again