The Tower is a large structure made by the machines. It appears to be constructed from the same materials as the Copied City, and is supported by columns spread across the overworld. It emerges from underground in Chapter 11 and is the final destination players will encounter in NieR:Automata.
The Tower is available for access as both A2 and 9S.
The elevator entrance to the Tower is located within the crater left behind after the Goliath attack that took place within the City Ruins. It is unlocked via hacking the three sub-nodes located near the entrance which in turn require the use of the three Access Release Keys found within the ResourceRecoveryUnits. This is done as 9S.
Access to the tower requires three nodes to be unlocked. Any intruder is greeted by a horde of machines. Devola and Popola assist 9S when attempting to enter, and succumb to their wounds from the ensuing battle. Upon going inside, Pod 153 retrieves the twins' memories from a data server.
Each node must be unlocked using its respective key. Each of them will have to be acquired from their respective ResourceRecoveryUnits as 9S.
The only way to advance up the tower, this strange staircase is guarded by corrupted YoRHa units.
Upon entering, 9S is greeted by an army of 2B copies. He falls through a cracked floor tile upon inspecting the last copy still breathing.
After A2 rids herself of the hacker threat, she begins to ride the elevator to the top of the tower, fending off the Goliath-class machine Ko-Shi.
Using the flight unit, 9S takes on the Goliath-class machine Ro-Shi.
Both androids reach their destination and reluctantly work together to defeat the Goliath-class machine lifeform Ko-Shi & Ro-Shi. During this fight, the player perspective constantly shifts, becoming more frequent as the machine loses health.