The Nether is a hellish Dimension of fire, lava, and dangerous monsters. Many ruins litter the burning chasms of the Nether- remnants of a greater age. Adventurers braving the blazing fires and horrific creatures are rewarded with bountiful treasures.
As hellish as this realm was, it didn't stop the ancient humans from venturing this realm. The Nether held lucrative commodities such as glowstone, nether wart, and many valuable building or brewing materials. Massive strongholds were built in the nether with the intention of mining and farming these resources. The humans brought pigs as food, and farmed a form of fungus called nether wart both as a brewing ingredient and a cheap pig feed.
During the age of the Great Wars, the Nether inhabitants had perished- degrading into the undead known as the Wither Skeletons. The pigs subsisted off of the nether wart, and stole weapons from the humans' end strongholds later into their evolution. They became the race of Pigmen.
It is unknown what happened, but the Pigmen may have suffered a large catastrophe to their society, killing many of them and turning them into the hostile Zombie Pigmen.
The Nether was not developed much in the Aetheria Server. Despite receiving significant work, the Nether is quite undeveloped compared to other dimensions. (the nether update does not exist in Aetheria)
(See main article Lavacrest)
The hamlet of Lavacrest is a stronghold of monsters from all different dimensions who fight against the forces of Herobrine, perhaps recruits from native monster populations or defectors of Herobrine's army. They are adept at crafting like any Aetherian or Terrarian, and posses, an intelligence unheard of in monsters.
The stronghold is a well-hidden city of netherrack and nether brick carved into a mountain, where monsters are free to resist the tyranny of Herobrine.