This Quest is obtained in The Gullet, an area of Neketaka. Head inside Enoi's house and speak to him. He will tell you of the struggles the Roparu are having, and ask for help.
While speaking with Enoi, you will learn that there are several ways to do this quest. You can speak to Prine Aruihi, talk to the Dawnstars, or go talk to Mad Morena.
Our suggestion, is head nearby to Pitli's house and speak to her. She will tell you that she'd like to help, but her hands are tied. Ask her about the Dawnstar to learn that you should go speak to Saewyn and tell her Pitli sent you.
Saewyn is found in the Temple of Guan in the Sacred Stair district. Speak to her, and you can either tell her that you will convince the Queen to help you, or you can tell her about the Principi. We're opting to speak to the queen, but either option works.
Now you have to go and talk to prince Aruihi in Serpent's Crown.