The Evolved Arctic has been described as the Nether on Earth, which is quite accurate. Several nether mobs spawn here, including blazes, wither skeletons, and ghasts. This is not a place for the weak. It's dangerous during day, but when the sun sets and even worse creatures come out, only the strongest will survive.
However, it wasn't always this way. In the past, it was green, and great Dwarven cities were built here. Not much is known, but their are a few ruins sprinkled around. Interestingly, only their temples have survived. The walls have been degraded and the ceilings have collapsed. Some sand has been enchanted and become "evolved." There are a few pieces left here which hold the secrets to how the dwarves disappeared and how the biome became an arid desert wasteland filled with nether mobs.
A new mob seen nowhere else also roams this biome. It is known as the Arid Skeleton. Without a source of string, it has evolved to fight melee style instead of with bows. Years in the desert have turned these monsters into tough warriors. There bones are stronger than average ones, and they sometimes carry better loot on them.
Other adventurers have also reported seeing occasional turkeys wandering these lands. No one knows why they have come here, but some suspect the dwarves used to raise and eat these creatures.
Cactus Bugs are small animals that probably survive by eating cacti. They usually travel in groups and attack anyone they see.
Basilisks slither across these sands, searching for prey. Their strong and venomous bite has taken down countless adventurers. They are notoriously strong in both damage and health. Only brave, or stupid, fighters will challenge this boss, though it does yield important loot.