The Druid Guardian is first seen in the opening of How to Betray a Dragon's Hero, titled: 'The Cursed Island of Tomorrow'. Desperate to keep the vast amounts of land the Uglithug Tribe seized after the fall of the Kingdom of the Wilderwest, UG the Uglithug lands on the shores of Tomorrow with the supposed King's Lost Things. To represent Toothless, UG presented the Druid Guardian a Trotterdragon whose teeth had been pulled out. The Druid Guardian inspects UG's King's Lost Things, only to quickly find that they are fake. Angered that UG came to Tomorrow with fake Lost Things and that he harmed the defenseless Trotterdragon, the Druid Guardian berates UG. The Druid Guardain then calls forth the Dragon Guardians of Tomorrow, who incinerate the defeated Uglithug Chief. Due to the fact that the entire Barbaric Archipelago was desperate for a new King of the Wilderwest to end the Second Dragon War, the Druid Guardian sighed disappointedly, while petting the head of the Trotterdragon, as he had hoped UG was the true King once and for all.
The Druid Guardian later appears again at the end of the book. Alvin the Treacherous, Excellinor the Witch, and the rest of the Alvinsmen land on the Singing Sands of the Ferryman to meet the Druid Guardian so he could inspect the King's Lost Things. The Druid Guardian is seen rowing towards the sands to meet the people who had landed there. His oncoming presence made the witch extremely nervous, as she knew that there was no room for error. The Druid Guardian finally reached the shore, and stepped out of his boat, stood directly in front of Alvin and stared at him, suspiciously. The Druid Guardian then asked Alvin if he was "he-who-would-be-king?". To which Alvin replies with a quick "yes". He then asks Alvin if he is the one that all the tribes of the Archipelago chose. To which the Dragonmarker prisoners protest with the Witch attempting to drown out with her own voice and claiming that they have some desenters. The Druid Guardiand responds, saying that it doesn't matter as long as they have the majority. He then asks them if they brought the King's Lost Things. Alvin says that he has and brings them forth. The Druid Guardian inspects them. When he inspected Toothless, he brought him out of his cage, with Toothless protesting that he isn't Alvin's dragon, but rather Hiccup's dragon. The Druid Guardian responds saying that it doesn't matter who he belongs to, but rather who brought him here. After the analysis is complete, he announces that Alvin's things are real and agrees to crown Alvin. The Dragonmarkers then arrive on the Singing Sands claiming that Alvin can never be king. Stoick and the witch get into an arguement, with the witch claiming that the Druid Guardian already inspected the things and agreed to crown Alvin. The Druid Guardian responds, saying that is the truth. During the argument, Valhallarama claimed a blood feud after finding out that the witch killed Hiccup. The Druid Guardian chimed in and told everyone to stop or the Dragon Guardians of Tomorrow would kill them. He then commanded the Dragon Guardians to give death by airy oblivion to anyone who lands on Tomorrow in the next 24 hours, as the king has been found.
The Druid Guardian is an old man with a long beard that stretches to the ground. He is bald and has a long pointy nose. He also doesn't have very many teeth. Before he removed it in How to Fight a Dragon's Fury, the Druid Guardian wore a blindfold over his eyes.