HTTYD riders meet the nine realms

The shimmering rift of the Hidden World hadn't just been a sanctuary; it was a doorway. Hiccup, clad in his blackened, obsidian-like dragon scales, sat atop Toothless as they hovered in the strange, electrified air of a massive underground cavern—one that looked nothing like the maps of the Archipelago. Beside him, {{User}} adjusted their own gear, their dragon chirping warily at the sight of the sleek, modern-looking metal structures and glowing lights below. Behind you, the rest of the riders—Astrid, Fishlegs, and the twins—were already reaching for their weapons, their eyes wide at the sight of four teenagers standing on a high-tech platform. "Hiccup," Astrid hissed, pulling Stormfly into a defensive bank. "Those aren't hunters. What are they wearing? Is that... fabric?" Hiccup didn't answer immediately. He looked like death itself, his mask's green lenses fixated on the small group below. To the Nine Realms teens—Tom, Jun, D’Angelo, and Alex—the sight was terrifying. They weren't looking at "Hiccup the Hero." They were looking at a legendary wraith from ancient history books, a shadow-clad warrior mounted on a "mythical" Night Fury that was supposed to have been extinct for over a thousand years. "Thunder, stay back!" Tom yelled, his voice cracking as his own dragon, the white-and-black Night Light, let out a nervous warble. Hiccup finally retracted his mask, his face scarred and weathered by years in the wild, his gaze cold but curious. He looked down at Tom’s dragon—the unmistakable lineage of Toothless staring back at him through the centuries. "You," Hiccup’s voice was raspy, unused to speaking to humans. He pointed a gloved hand toward Thunder. "Where did you find a dragon of that bloodline?" The modern teens stood frozen. They had spent months hiding their "secret" dragons, only for a literal ghost from the Viking Age to drop from the ceiling. "We... we're the Dragon Club," Tom stammered, looking up at the terrifying figure of Hiccup and then at {{User}}. "Who are you? You look like you just walked out of a museum... or a nightmare."