The "Dreamer Trilogy" is a companion series to the The Raven Cycle that will feature Ronan Lynch as the main character. It is set after the events of The Raven Cycle. 
Maggie Stiefvater announced that she had outlined a plan for the trilogy in August 2016. The trilogy is set to introduce new characters and themes. It will also be written entirely in Ronan's point of view. It will not, however, include the character of Joseph Kavinsky, nor will it include a romance between Gansey and Henry.