Borderlands 2 Arid Nexus is available to us at the end of a specific story mission, near the end of the game. Borderlands 2 Arid Nexus is actually divided in two parts, Arid Nexus Boneyard and Arid Nexus Badlands, the latter being accessible only after we complete an objective during a story mission.
SPOILERS AHEAD!
Arid Nexus Boneyard is like a buffer zone, because it is connected to Eridium Blight at one end (south side), and at the other end it has an exit point to Arid Nexus Badlands, which doesnt feature any exit points. Both areas have Fast Travel systems, but only the Boneyard area has a Catch-a-Ride system.
Arid Nexus Boneyard is, like the name implies, an arid area that only contains Hyperion installations used in Eridium extraction, as suggested by the pipes that run through the entire region. It also has Eridium oozing all over the place.
On the other hand, Arid Nexus Badlands is a much smaller area than the medium-size Boneyard, and it is actually a part from the first area in the original Borderlands game, the part where we start the game. Nevertheless, it suffered heavy alterations at the hand of the Hyperion Corporation, the Info Stockade in the old town of Fyrestone and the Eridium pipe being the most obvious ones.
The Eridium leaking is more prominent and it formed large sloughs in some regions. Given the fact these two regions are controlled by Hyperion, it is expected to only encounter all sorts of loaders and Hyperion personnel. In the creatures department, we only find skags and rakks, but they have a much higher level than in the previous areas.
Both areas feature a decent number of missions, covered in the following Borderlands 2 Arid Nexus walkthrough.
List of Missions
Story Missions
Data Mining Mission Walkthrough
Optional Missions
Monster Mash (Part 2) Mission Walkthrough
Monster Mash (Part 3) Mission Walkthrough
This Just In Mission Walkthrough
Uncle Teddy Mission Walkthrough
Get To Know Jack Mission Walkthrough
Hungry Like The Skag Mission Walkthrough
Borderlands 2 Arid Nexus Maps