The Snow Girl Ending is an Ending in Prisoners of the Elder One. It occurs after telling Satsu that her love is dead (whether this is true or not).
In a rage, Satsu freezes Erik, who is then reborn as a young and demure yuki-onna. While she learns to conquer her need to drain heat, and her sweet personality makes her popular in the mansion, she loses all memories of her former life, meaning Tiffany is forever trapped.