Emmaco is the ship between Emma and Marco!, Though they are from different world's Emma is a time Traveller
And she can go into the past and future! (Plus in the fanfics Emma and Marco have a very strong relationship, along with Marco seeing this strange girl in his dreams, and then seeing her in real life!, Star and Marco think she's a threat at first but when she tells Star and Marco who she is Star releases that Emma is her real -what ever eclipsa is!- and the mother of febe-the red one! And she had been crystallized for over 300 years! And that she is forever the age of her loved one! Though she had no one that cared for her! But Emma and Marco start falling in love with each other!, And at the end they kiss and Emma says this happens to me a lot! And it is know wonder this happens to her a lot, she is the queen of love/blood moons!