Ancient City Portal Should Lead to a Sculk/Warden Dimension

The mysterious reinforced deepslate structure in the Ancient City could become a portal to a dimension connected to the Warden and Sculk.
An ancient civilization may have discovered this dimension and opened the portal, allowing Sculk and Wardens to spread into the city and eventually destroy it.
Deep inside the dimension could live a massive Warden-like boss with huge arms and a glowing exposed ribcage. Instead of a Sonic Boom, it could smash the ground, creating a circular shockwave that players must jump over or be thrown into the air and heavily damaged.
The boss’s roar could sound like a Sculk Shrieker and summon Wardens during the fight. This could hint that Wardens respond to Shriekers because the sound resembles their boss’s call.
The portal could require Ancient City loot to activate, such as Echo Shards and Disc Fragments. Players would need to explore the city and complete Music Disc 5 before opening it.
This could give the Ancient City structure and its unique loot a new purpose while expanding the mystery of the Sculk and Warden.