Gorgeous Carat Galaxy (Boy’s Love manga)

Florian takes Ray and Lila to a distant relative’s estate/castle known for its unique garden with sculptures of monsters. Jacques, who now oversees the estate, is forced to sell some of its treasures for upkeep and to take care of his cousin, Eleonora. Things are complicated by a blizzard and the arrival of Jacque’s fiancee, Charlotte, who abhors Eleonora. A mysterious figure starts to attack guests, and Eleonora kidnaps Florian, who she sees as a symbol of the time in her childhood when she was still innocent. While searching for Florian, Ray and the others discover a complex series of secret paths.