Ryoko's Guide to the Yokai Realms, pg 221
Prerequisite: Tatsumi
You are able to shift your colouration, a rare ability possessed by few of your kin, granting you the following benefits:
• You have advantage on Stealth checks made to avoid being seen.
• Choose one colour from your Koi Dragon Colour trait when you select this feat. When you use your Slumbering Dragon or Heartening Breath trait, you can choose to empower ability checks, attack rolls, and saving throws associated with either your primary colouration or the one you chose with this feat.