Machine God: Nirvana (機神・ニルヴァーナ Kishin: Niruvāna, localized as Deus Machina: Nirvana) is an Arch-Enemy Event Weapon in form of automaton. It is 195 cm in length and feminine in appearance. Its wielder is Carl Clover, and previously Celica A. Mercury.
During the Great Dark War, Nine made Nirvana as Celica's bodyguard as she had no means to protect herself from the dangers at the time. She was turned into an Arch-Enemy when Nine divided Highlander: Takemikazuchi's core, and used one of the parts for Nirvana. By the end of the war, Nirvana was sealed away along with other Event Weapons.
Many decades later, Nirvana would be recovered by a mercenary troop of Seventh Agency from the 4th Hierarchical City "Naobi" and end up in Relius Clover's possession. After her retrieval, Relius noted that Nirvana had no physical defects, but was empty inside. He used his daughter, Ada Clover's body and soul to restore her, but was apparently only partly successful. With time, Relius Clover created something similar to Nirvana, named Detonator: Ignis.
At some point in time, Carl found Nirvana after Relius abandoned her and, according to Relius, had also modified her and increased her capabilities.
Nirvana's effect on the user's mind is a controversial subject. According to Litchi, Tager and Hazama, she inflicts madness on her owner's mind or possesses them. On the other hand, Hakumen stated that Nirvana is driven by its owner's killing intent and that others are just trying to shift the blame.
Nirvana has also shown signs of protectiveness over Carl even when Carl is not commanding her, further strengthening Carl's belief that it is Ada and not Nirvana. She has protected him from deadly blows, despite Carl pleading for her to not protect him. She has also attacked Noel and Bang Shishigami when they proceeded to touch Carl despite their harmless intent. Whether this is because of Nirvana holding Ada's sisterly affections for Carl or Nirvana simply protecting her master is currently unknown.
- "Nirvana" is a transcendent state of enlightenment and tranquillity in Buddhism.
- Nirvana is shown to have soulless eyes in present time, but she did possess normal pupils during the Great Dark War.