CPU from Final Fantasy IV (PSP).
The CPU (せいぎょシステム, Seigyo Shisutemu?, lit. Control System), also known as the ControlSys, ADS, or Control Node, is a boss in the Final Fantasy series. It debuted in Final Fantasy IV during the boss battle inside the Giant of Babil.
Appearances
Final Fantasy IV
CPU is the penultimate non-optional boss the party encounters in the main storyline. The controlling unit of the Giant of Babil, CPU directs the giant's actions. Cecil and company realize CPU is the giant's only weak point, and fly the Enterprise inside to stop the war machine. It is assisted in battle by the Attack Node and Defense Node.
Final Fantasy IV: The After Years
CPU is a boss found in the Crystals: Subterrane.
Final Fantasy XIV
The ADS (Allagan Defense System) appears as a boss in
The Binding Coil of Bahamut - Turn 1 and Turn 2. In both battles it is assisted by the Attack Node and Defense Node, along with several other nodes. During the second encounter, the party must fight through a gauntlet of other nodes with multiple branching paths to reach the ADS. Defeating each node grants a buff to the ADS and others nodes, while preventing the ADS from using that node's signature ability.
Final Fantasy XVI
The Control Node is a boss encountered in Reverie.
Dissidia Final Fantasy Opera Omnia
The CPU is a boss that is fought in Act 2, Chapter 5.
Pictlogica Final Fantasy
Final Fantasy Record Keeper

CPU is a Nightmare-class boss in the Quadruple Foul Record in the Nightmare Dungeons. To face it, the player must first defeat Gyges the Great, Humbaba, Tiamat, and Barthandelus.
Final Fantasy Brave Exvius
Etymology
The CPU, or Central Processing Unit, is the portion of a computer system that processes the arithmetical and logical operations of the computer, making it analogous to the computer's brain.