In this world Marco is King Moon. And Star is Queen Star.
Marco had to destroy Eclipsa's husband for his place in the throne, since Eclipsa's husband was "married" to Moon. And by married I mean Satan had Moon trapped in a horrifying cycle of life and death.
Thus by freeing Moon, Marco is wedded to moon in this world. Star is their daughter now, and had things gone according to plan, you dark witches would of had your horrifying fun with Star's torture.
The moar you know. Stay salty, forever.