The Viridian Gate: A 7th Level Adventure for 5th Edition

Long ago, when the world was young, the many realms were interconnected via a series of magical portals. These Viridian Gates, built by the elves prior to their fall from grace with the gods, could transport you from one place in Arden to another, or sometimes even to the Feylands or Shadowrealm. When the gods smote the elves for their hubris, most of the gates were destroyed in the subsequent cataclysm. One lone gate, however, managed to survive intact deep beneath the surface in a dark abandoned elven ruin. This gate led to a strange realm somewhere deep in the void where the monsters and elder gods slumber. When the elves activated it, they awoke something terrible and were forced to flee the underground complex where the gate resided.

In the centuries since, the gate has remained dormant. Without a substantial power source, it simply simmers and flickers now and then as the latent energy within swells and crashes. Recently, however, a wizard's experiment accidentally provided the gate with a new source of energy. The gate opened once more and eldritch horrors began spilling out. Unable to bear the light of the sun above, they lurk in the shadows, prowling and hunting the forest around them at night before retreating with their prey in tow as the first glimmer of sunlight begins to rise over the horizon. Their most recent hunt ended when they made off with the small child of a traveling clan of elves, driven back by bow and blade. Injured and unable to pursue, the elves seek the help of a passing group of adventurers to reclaim their stolen child and deal with the terrible monsters who took it.