This article contains content from the EvaGeeks.org Wiki article S² Engine. Please view that page's revision history for the list of authors.
Eva 01 devouring S² Engine.png

An (Super Solenoid) Engine (S²機関, S² Kikan) is a source of power from Neon Genesis Evangelion.


Also referred to as an S² Organ, the S² engine is an organ located within the core of an Angel[1] which grants it limitless energy at no cost. While not born with them, Evangelion can make use of S² Engines,[2] freeing them from the need for their internal batteries of umbilical cables.

The name comes from Dr. Katsuragi's Super Solenoid Theory.[3] He had intended to create an actual device ("S² Engine") based on the principles established with his theory and verified with Adam's power source, but this never came to be.[4][5] Despite his failure, after Dr. Katsuragi's death the S² Engine would eventually be perfected and produced in secret by SEELE for use with the Mass Production Evangelion.

Why the name "engine" was applied to what is unarguably a flesh-and-blood organ[6] is never stated. It appears consistent with the show's tendency to disguise the inherently biological with terms of mechanical connotation. Incidentally, written with different kanji, 器官, "kikan" does mean "organ", providing a bit of wordplay that doesn't translate into English.


Neon Genesis Evangelion

Core recovered from Shamshel.

A mostly-intact S² Engine is obtained from the corpse of Shamshel and sent to Germany for further study by the Third Branch's Energy Analysis Unit.[7] After the S² Engine is restored, NERV's Second Branch in Nevada undertakes an experiment to install it into Unit-04, which results in the disappearance of the Eva, related facilities, and everything and everyone else within an 49-kilometer radius, swallowed by a Sea of Dirac.[8]

Despite the loss of the restored organ, the research data is preserved in Germany and progress towards completion of the Mass Production Evangelion outfitted with artificial S² Engines continues.[9]

A berserk Unit-01 is eventually able to obtain an S² Engine from the Angel Zeruel by physically devouring the organ and assimilating it as its own.[6] According to SEELE, this acquisition makes Unit-01 an "absolute being" and the living embodiment of a god.[10] The S² Engine is said to be the only thing (aside from, presumably, a soul) required to "complete" an Eva and bring it to a level of existence equal to Adam's.[4]

The End of Evangelion

Mass Production Evangelion Reactivating.

During the invasion of NERV Headquarters by the JSSDF arranged for by SEELE, the nine completed mass production Evangelion, each outfitted with a fully operational artificial S² engine, are dispatched to stop Evangelion Unit-02. During their battle, Unit-02 seamingly manages to destroy all the mass production units. However, because their engines remained intact, the units were able to reactivate and completely destroy Unit-02.


  • The "Fruit of Life" is considered an alternate term for "S² Engine",[4] and exists in contrast with Fruit of Knowledge. According to Fuyutsuki, Unit-01 had attained power equal to that of a god's upon acquiring both Fruits.[11] The Fruit of Life is a reference to Tree of Life of Genesis, the fruit of which was said to bestow immortal life.
  • An intact S² Engine is never seen in the show, although it is known to be double-helical in structure, much like DNA.[4] (Regular solenoids are shaped like spirals.)


  1. While never stated directly, the location of the S² Engine is strongly intimated in Episode 05 during Shamshel's autopsy, and careful observation shows that Unit-01 is targeting Zeruel's core while "taking the S² Engine into itself".
  2. No reason is provided, although numerous speculations exist.
  3. Neon Genesis Evangelion. Episode 21'.
  4. 4.0 4.1 4.2 4.3 Neon Genesis Evangelion 2. Classified Information. S² Engine.
  5. Evangelion Chronicle.
  6. 6.0 6.1 Neon Genesis Evangelion. Episode 19.
  7. Neon Genesis Evangelion. Episode 05.
  8. Neon Genesis Evangelion. Episode 17.
  9. The End of Evangelion. Episode 25'.
  10. Neon Genesis Evangelion. Episode 20.
  11. End of Evangelion. Episode 26'.