OH BOY IT’S BEEN A WHILE AND I WAS IN THE MOOD!!!  
SO  
Prince Eclipse! Son of Princess Luna and a changeling who is currently missing in action.  
The particular changeling snuck his way into canterlot and was trying to get revenge for his queen by getting close to one of the royal sisters in disguise. He knew Celestia wouldn’t ever fall for anyone after Mirror!Sombra and she was too smart to think that Mirror!Sombra could have reverted back and come for her somehow, so he went for Luna instead disguised as one of her bat pony guards. However partway through his revenge plans he start to fall for her too, which presented a huuuuge dilemma. When she told him he was pregnant, he panicked and came clean about who he really was and what his initial intentions were, which clearly freaked Luna out. She was more confused and hurt than upset, but he ended up running off thinking she would never forgive him and never came back. Luna misses him a lot, but she has no idea what he really looked like or if she could even pick him out from a crowd of other changelings, so unless he ever returned of his own free will, he’s gone.
 
And thus Eclipse was born (A total eclipsssssse of the heaaaart)  
He’s a bit younger than Siempre, but still older than the next gen mane 6 crew. Even though they’re cousins, they grew up as brothers. Being part changeling, Eclipse can change his appearance at will, although he quite likes how he looks. When he was younger, instead of involuntary magic outbursts, he would flip through a bunch of different appearances on accident and end up scaring Luna by thinking she lost him. There were more than a couple incidents of her coming back from taking him to a park with the wrong foal.
 
Grown up, Eclipse is a pretty big flirt and a trouble maker. One of his favorite pas-times is running around looking like Siempre just to stir up confusion, but he gets caught when he forgets that he can’t be using his eyes to look around as Siempre is blind. He kisses everybody. All of his friends get many platonic cheek kisses, and nothing delights him more than getting them back.  
He does end up with Prince (Tanzanite) as in, in a relationship. After Prince moved on from his unrequited crush on Zap Apple, Eclipse was happily waiting to win him over. They met when their friend group (as in Enna and Zap Apple and Cherry and Dawn and Enna) was visiting the castle. Prince stormed off still steaming over Enna running off to see Siempre, and ran right into Eclipse, who was disguised as Siempre at the time. Prince was very confused and very outraged at “Siempre”s sudden attempts at flirting and just at his presence in general until Eclipse dropped the facade. That was certainly an experience.
 
As always, if anyone has any headcanons you should lemme knoooooooooow ;ooo I would love to have more fuel to draw my next gen babies again. I miss them a bunch.
 
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