This one has been in the series since Brawl. It’s based on the Fire Emblem series, but not after one true castle in any of the games if I’m not mistaken. The first part of the stage starts on the top of the castle walls. Which is basic and simple.
Then you fight a more complicated map when the screen takes you inside the castle.
And at the end, you somehow end up fighting in some kind of volcano.
While far from my favorite map, I’ve had good memories here with Castle Siege.