Loving Haiku of Horrors. I adapted Kaidan to L5R because of it, making it first encountered by a Yobanjin-like group for the Anu, then the Mantis used Kura Island to hide enemies of the Gozoku, returning them before surviving ships from the Battle of the White Stag that didn't get swallowed in the Sea of Shadows for the Korobokuru. The Rokugani returned during the Great Famine when the Mantis and Tortoise worked together to help Rokugan start a colony that grew during the Eighth Century Crisis and abandoned by the Mainland pre-return of the Unicorn, just to have their return cause Rokugan to learn about the Oni Lords and the Emperor to declare travel there forbidden fearing the land to be tainted. Sojobo became a Ronin raised by the Tengu tribe of Kenku. History is slightly condenced from there, replacing Emperor/Empress with Governor and Shogun with Colonial Guard Rikugunshokan, etc. The Yokai became an alliance of the tribes of the Five Ancient Races, Naga until the Great Sleep, and Nezumi after the Great Sleep.

Honestly, i'd love to see you tackle the Capital, Fukuhara-kyo. Whether just doing a 30 Haunts For... with maps or a full adventure.