Majesty: “It was foolish of you to come here tonight, Catrina. The Alicorn Sisters are on their way.”
 
Catrina: “By which time I shall be gone, and you… shall be dead.”
 

 
So, more headcanon ideas, this time, with some g1 stuff, ‘cause why not.
 
Majesty and Catrina were former friends and fellow magic users, until Catrina wanted more power. She insist that she and Majesty could rule the world together, but Majesty refused so they broke up. Catrina was then caught and banished and Majesty became queen until her kingdom got invaded by Tirek’s army.  
Many, many years later, plot stuff happens, Majesty remained ageless until all of her old foes are to be rid off, Catrina returns planning on killing the most powerful magic users so that no one can stop her, she tries to kill Twilight, Majesty arrives and the two battle.
 
Write the set up yourselves if you like to.