Machine God: Nirvana

Machine God: Nirvana (機神・ニルヴァーナ) is a form of automaton. It is 195 cm in length and feminine in appearance. Its wielder is Carl Clover, and previously Celica A. Mercury.

Information
During the Great Dark War, Nine made Nirvana Celica's bodyguard as she had no means to protect herself from the dangers at the time. By the end of the war, Nirvana was sealed away per Celica's request.

Many decades later, Nirvana would be stolen by Seventh Agency's assault squad from the Controlling Organization and end up in Relius' 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.

During the events of creating the 13th Prime Field Contact, Relius had installed an Event Weapon Imitation in her so she could be moved, but only for a few minutes. After fighting off the Black Beast from the Kiln along with Ignis, Nirvana, at the behest of Kokonoe, stabs Relius through his abdomen and disappears afterward, along with Relius and Ignis.

At some point in time, Carl was somehow able to obtain Nirvana and, according to Relius, had also modified her and increased her capabilities. This torments Carl, as Relius kept alluding to Carl that he could not have failed to notice the object inside of Nirvana, claiming it was Ada's soul and that souls are actually just objects to be used as tools. Repairing Nirvana also reminded Relius of when he was Carl's age, and once again to Carl's dismay, points this out.

It is suggested that Nirvana is not a combat Arch-Enemy Event Weapon, or at least not on the same level as others. Hakumen told Carl Clover that "[Nirvana]'s hands was never meant to be dirtied". Rachel Alucard also informed Carl that Jin Kisaragi and Noel Vermillion's Arch-Enemy' were more powerful. This does not mean Nirvana is not strong; Nirvana, when teamed with Carl, is a very strong fighter, injuring many strong characters throughout the series, though this is mainly through sneak attacks.

Nirvana has displayed several fighting techniques. She is primarily a melee weapon, on Carl's orders she will either punch, throw or stab an enemy. Her hands appear to change form into several types of blade, which serves as her main method of attacking. She also has the ability to teleport, shown in combat when materializing next to Carl at his command or teleporting Litchi Faye Ling and Carl a fair distance away from Relius. Nirvana also holds a powerful bomb, which is Carl's Astral Heat.

Nirvana's effect on the user's mind is a controversial subject. According to Litchi, Iron 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.

Trivia

 * 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.