Hidden Palace Zone (Westside Island)

"Not to be confused with Hidden Palace Zone (Archie)"The Hidden Palace Zone is a location that appears in the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics. It is an underground region beneath the Mystic Cave Zone.

Early days
In ancient times, the trolls, or the Second Great Civilization, had used the Hidden Palace Zone as a mine. They dug up emeralds which increased their powers. It became inactive after the trolls became nearly extinct.

Double trouble
Many years later, Doctor Eggman had come to this zone in his quest for power. He had fought Sonic the Hedgehog and Miles "Tails" Prower here, where the mad scientist was defeated and forced to retreat.

Shattered
After Walter Naugus' plans were foiled by Dr. Eggman, he retreated to this zone to increase his powers through the use of emeralds and Master Emerald shards. Knuckles and Amy came to the zone later on in search of the remaining Master Emerald shards. They were joined by Team Dark, who were looking for Eclipse the Darkling, a rogue alien.

Naugus crystallized Omega so that the latter could get rid of Shadow, Amy and Rouge. Naugus then shape-shifted into a purple echidna named Nixus, tricking Knuckles into believing that he was not the last echidna. "Nixus" led Knuckles to a secret chamber accessed by Hidden Palace's organ where they could assemble the Master Emerald in peace. Knuckles, however, was crystallized and Nixus revealed himself to be Walter Naugus. Naugus stole Knuckles' shards and kicked him out of the secret chamber so that he could assemble the pieces himself. Knuckles was forced to regroup with the others as they faced Crystal Omega.

Trivia

 * The Hidden Palace Zone is based off of the re-released zone in the 2013 version of Sonic the Hedgehog 2