altera the santa (fate)
Fate/Grand Order character.
The Santa version of Altera appearing in the Meikai no Merry Christmas event. As a result of wearing light clothing during the winter and going into the underworld, which is colder, Santa Altera has developed a fever which makes her nicer and more feminine than her Saber form, and messes with her mind to the point she thinks she's from the Ram Galaxy and not Earth.
Altera's sheep is named Zerco.