Logos React

is one of the Seven Superweapons of Atlas, developed and kept by Atlas of the Mage's Association.
==Characteristics==
Zepia Logos React.jpg|Zepia Eltnam Atlasia observing Logos React.
Bird of Hermes.jpg|The Bird of Hermes.
Logos React is a Pseudo-Spiritron Computer similar to the Moon Cell or a Philosopher's Stone. It can record and recreate minds, and through its computation ability, it can calculate multiple possibilities to create countless virtual worlds inside itself.
Once you input your desired conditions, it simulates a limited observable environment in which to conduct the thought experiment in a virtual world that is essentially indistinguishable from reality. Its parameters can be set however one likes, so it could be said to create real experiences through a dreamlike state. On a limited scale, one can use Logos React to see how hypothetical versions of history would play out.
If the simulation inside Logos React discovers a contradiction, the simulation begins to collapse.Lord El-Melloi II Case Files Volume 7: case. Atlas Contract (Lower) - Chapter 4 Part 2
Like all of the Seven Superweapons, Logos React was created to save humanity but also has the potential to destroy it if something goes wrong.Lord El-Melloi II Case Files Volume 7: case. Atlas Contract (Lower) - Chapter 5 Part 1 When Logos React discovered a paradox in its programming where it had "died" despite being an inanimate object, it started to malfunction and could potentially destroy half of Wales.Lord El-Melloi II Case Files Volume 7: case. Atlas Contract (Lower) - Chapter 5 Part 1
Zepia Eltnam Atlasia can observe what is happening inside Logos React with a crystal ball.Lord El-Melloi II Case Files Volume 7: case. Atlas Contract (Lower) - Chapter 1 Part 4
==Role==
===Lord El-Melloi II Case Files===
The Mystic Code Add is also known as the . A replica of Logos React created by a director of Atlas long ago at the behest of Morgan le Fay and Blackmore Cemetery, Logos React Replica uses the extreme calculative ability inherited from the Seven Superweapons of the Atlas Institute to seal Rhongomyniad within itself. Logos React Replica copied the personality of Kay of the Knights of the Round Table, and under certain extreme conditions the Replica can project Kay outward as an existence similar to, but not the same as, a Servant. This Kay appears hazy and not fully "there", and can only manifest for a few hours.Lord El-Melloi II Case Files Volume 6: case. Atlas Contract (Upper) - Epilogue
Blackmore Cemetery currently has Logos React because they possess one of the seven Contracts of Atlas.Lord El-Melloi II Case Files Volume 6: case. Atlas Contract (Upper) - Chapter 2 Part 4 Zepia Eltnam Atlasia, the current director of Atlas, sends Lord El-Melloi II and Gray into the virtual simulations inside of Logos React,Lord El-Melloi II Case Files Volume 6: case. Atlas Contract (Upper) - Chapter 3 Part 4 and later Flat Escardos and Svin Glascheit with Flat's magic hacking, are able to interfere with Logos React's simulation to help Gray and El-Melloi II out.Lord El-Melloi II Case Files Volume 7: case. Atlas Contract (Lower) - Chapter 2 Part 6 When Logos React begins rampaging, Zepia is able to stop it almost single handedly.Lord El-Melloi II Case Files Volume 7: case. Atlas Contract (Lower) - Epilogue
The Corpse King is a recreation of Artoria Pendragon's mind using Logos React, similar to the case with Kay and Add. The plan of Morgan le Fay and Blackmore Cemetery was that by combining the mind of the Corpse King, the body of Gray, and the soul of Artoria (summoned as a Servant in the Holy Grail War), they would be able to bring about the resurrection of King Arthur. The Corpse King also serves as Logos React's avatar, and her death is what caused it to malfunction during the events of the story.
===Fate/Grand Order===
 is another copy of Logos React belonging to Sion Eltnam Sokaris. It was a birthday gift to her from Zepia.
With the Generic version, Zepia was unable to get the setting meant to smooth over the discrepancies between the simulation and reality working properly, so as more paradoxes, inconsistencies, and bugs in the created world pile up, its environments eventually become Singularities. It is essentially a Singularity generator. Seeing the simulation through to its conclusion can cause the Singularity to vanish.Fate/Grand Order: Cosmos in the Lostbelt - GUDAGUDA Final Honnōji​ - Section 1.5: Formation! We are the Chaldea Kaientai!
It was used to create a simulation of Sengoku Era Japan.
==References==
Category:Mystic Codes
Category:Terminology in Lord El-Melloi II
Category:Terminology in Fate/Grand Order
Category:Inventions of Atlas