Gospel

The Gospel (ゴスペル), also known as The Black Orbment, is a powerful and mysterious artifact in and  that had the ability to shut down nearby orbments. This ability was called as the Orbal Shutdown Phenomenon. While the exterior looks ancient, the orbment appears artificially replicated with modern materials with no seams or maintenance panel to access the interior. There is no caliber inscribed on its surface.

In Trails in the Sky SC, the Gospel is revealed to be part of a plot formed by Ouroboros member and Anguis Georg Weissmann. This plot was known as the Gospel Plan, in which he planned to bring back the Liber Ark which contained the Aureole, the Sept-Terrion of Space, which he wanted to obtain for his own use.

Principles
The Gospel is a tool created by the Aureole, which distributed the Gospels to the inhabitants of the Liber Ark. The Gospels had several functions: An identification tool, since every person on the Liber Ark had one, a way for the Aureole to distribute its own powers to create its miracles, and for some units, keys to operate the sealing mechanism of the Aureole. Celeste D. Auslese later disposed of these units to ensure the sealing mechanism was not tampered with. In the modern era, Ouroboros has created replicas of Gospels with which they conducted several experiments to create new keys to operate the sealing mechanism. Activating a Gospel results in the Orbal Shutdown Phenomenon; this phenomenon was assumed to be the function of the units before they were revealed to be keys to the Aureole. The shutdown is a side-effect of the Gospel creating openings for the Aureole's power which results in it spreading its protective measures, syphoning orbal energy to protect itself.

The Gospel is first seen in at the end of when Estelle and Joshua get a parcel intended for their father Cassius delivered containing a unit with the following note;

The Gospel is not brought up again until the finale of after Mayor Dalmore uses the Chronos Rod against Joshua, Estelle and Kloe after confronting him. The Gospel activates for the first time giving a black aura and disabling the effect of the Chronos Rod's freezing abilities. After this event Estelle and Joshua decide to go to Zeiss requesting professor Albert Russell's assistance in researching the mysterious orbment.

In, Estelle and Joshua arrive in Zeiss and find Professor Russell's assistance in researching the orbment starting with an experiment in analysing the orbment at his laboratory which again sets off the orbment's function of disabling orbal machina showing enough strength to disable to entire power grid of Zeiss. The next day the group decides to try opening up the orbment to realise they are only able to cut it open using pre-revolution machina which functions on gasoline instead of orbal energy. As the group leaves Professor Russell to deal with an issue at Elmo Village, the Intelligence Division, tipped off of the Gospel's whereabouts after last nights incident, instigates a covert attack to retrieve the orbment and kidnap Professor Russell to research the machinery further.

Estelle and Joshua realise that the kidnapping was executed by the Intelligence Division after they visit Leiston Fortress and the gate stops halfway when closing again indicating that a similar phenomenon as witnessed before is happening. The next day Estelle, Joshua, Tita and Agate decide to infiltrate after Dorothy shows further proof of the kidnapping plot. During the infiltration it is shown that Professor Russell has concluded his research handing it over with the Gospel to Lt. Lorence and Richard after which they leave.

During the Finale the Gospel once again appears and is shown to be used as intented after activating in the Sealed Area releasing the first seal of the Aureole's sealing mechanism in turn activating the Tetracyclic Towers across Liberl and releasing the Ring Guardian Reverie.

The Gospel appears once again during Chapter 1 after the group tracks down the source of various ghost sightings over the province of Ruan. It is tracked down to the Old Schoolhouse at Jenis Royal Academy and it's rediscovered secret underground level where Bleublanc has been experimenting with functions of the newest Gospel model showcasing how strong it is in showing its capabilities as an Orbal Projector.

The Gospel appears once again during Chapter 2 in the investigation of the earthquakes in the Zeiss region. After the party discerns that the earthquakes are instigated in some way they track down the source to the Hot Springs Fountainhead located in Elmo Village where Walter has been experimenting with the Gospel's enhancement capabilities by having it tethered to a device that monitors and influences the Septium Veins. Because the Gospel amplified it's power it became possible to create potent earthquakes on demand.

The next experiment, inevitably in Chapter 3, takes place at the harbor of Grancel when Kanone was waiting for a chance to find a suitable power source  for the Orgueille which ended up being the new Arseille-class orbal engine. Having this power source for the Orgueille Kanone sets out out for the castle being stopped in her tracks by the group and Royal Army after which she reveals the new experiment with the Gospel. The Gospel is incorporated on the tank as a means to weaponise the Orbal Shutdown Phenomenon rendering all orbal warfare unusable. Through some means the Orgueille itself is not rendered powerless. With the group having no means of protecting itself devising a dangerous plan to try and destroy the Gospel Kevin Graham steps in electing to destroy the Chronos Rod he is carrying. Destroying said artifact releases a large surge of latent orbal energy which was strong enough to overpower the Gospel's capabilities of syphoning orbal energy. After this the group is able to destroy the Orgueille and take in Kanone.

The fourth experiment is set in the Rolent region as the group is forced to land there because of a dense mist while travelling to the Bose region by airship. Later, as the group uncovers the source of the mist being from Mistwald Forest the group traverses to the central tree in it's center. As the group reaches the center they find out someone placed a Gospel on its base. Here Luciola reveals herself to the party, and while she does not acknowledge it to the party it seems that the Gospel was used to amplify the septium vein's power through the tree once again resulting in the vast mist around the Rolent region, after this she started using the mist to amplify the reach of her own powers as soon earlier by the party putting civilians in a dream-like comatose state. After the fight she takes the Gospel back and leaves after which the dense mist slowly fades.

The fifth and final experiment is set in the Bose region where Weissmann and Loewe travel to the Ancient Dragon's Dwelling where a dragon rests. Here Weissmann and Loewe strap a Gospel unit to its head as a means to control it after which Weissmann leaves. This experiment proves understanding on how the Gospel unit is capable of controlling the dragon's conscience which in turn results in the raging rampage leading to the destruction of Bose's Grand Market and the orchard of Ravennue Village. After the bracers tracking down the dragon to his lair, after Loewe's departure, they manage to destroy the Gospel unit through Agate's new augmented blade. After this the dragon reveals himself to be Ragnard and explains that while he was controlled by the Gospel unit he still had awareness of what was going on. After handing over goldia ore as a repayment for the damage he goes back to sleep.

After these five experiments led by the Enforcers of Ouroboros the organisation prepares for the final stage of the Gospel plan. After Estelle escapes the Glorious with Joshua enforcers Bleublanc, Walter, Luciola and Renne ascend upon the Tetracyclic Towers where the the mysterious devices have been activated for a while. Here the enforcers place their Gospel units once again properly activating the towers resulting in the opening of the alternate dimension which the bracer group has to traverse to reach the top of the towers. After a certain amount of time however the activation of the towers deactivate as an indication that it's part of the second sealing mechanism has been finished. As all four towers have been unsealed the final seal on the Liber Ark is broken resulting in it's reappearance in this dimension.

Finally, during the final chapter, the party gets their hands on an authentic Gospel unit distributed by the Aureole's system as it recognises Klaudia von Auslese as an inhabitant of the Liber Ark due to her genetical code being 73% similar to her ancestor Celeste D. Auslese. After this they use this gospel unit as an identification device to travel through the ark activating emergency passages and the light rail system.