Why Raeliana Ended Up at the Duke's Mansion (Korean: 그녀가 공작저로 가야 했던 사정, romanized: Geunyeoga Gongjagjeolo Gaya Haessdeon Sajeong, Japanese: 彼女が公爵邸に行った理由, romanized: Kanojo ga Kōshaku-tei ni Itta Riyū) is a South Korean web novel written by Milcha.

Eunha Park dies in modern day Seoul and gets reincarnated in a novel as an supporting character named Raeliana McMillan who eventually gets killed off during the original story.

To avoid her second death, she makes a deal with the male lead Duke Noah Volstaire Wynknight to pretend to be his fiancée in exchange for her silence regarding the whereabouts of the Royal Seal, information she knows from her prior knowledge of the original novel.

A digital English translation of the novel was published exclusively on the Tappytoon app, under the title The Reason Why Raeliana Ended up at the Duke's Mansion.

[16][17] It is produced by Typhoon Graphics and directed by Junichi Yamamoto, with scripts written by Mitsutaka Hirota, character designs handled by Haruna Hashimoto, and music composed by Keiji Inai.