In Chapter 24, the party found a room labeled “Brenton & Debis’ room,” and retrieved a set of wooden toy knights that registered psychic significance to Dora.
In Chapter 27, the party learned from Dr. Elbourne that Debis was likely the mysterious ghostly child lurking in the dark room between the East Ward and the Large Hall, and that he was in search of some birds.
In Chapter 28, Ray recognized that Brenton’s shadow lantern was what Debis was searching for.
In Chapter 31, the players learned his surname and that he had been very recently committed with his twin brother Brenton after their parents were slaughtered by bandits, right in front of them, on the highway south of Rozenport.
He was laid to rest in Chapter 35 (Part 2) when the party returned his shadow lantern.
First Reference: Chapter 24
Other Notable References: Chapter 27, Chapter 28, Chapter 31, Chapter 35 (Part 2)