The Oz series, an abbreviation for Originator Zero (根源たる虚無), were created by the Gnomes of the Black Workshop. They are beings with a complete link to a combat shell. They are both human and weapons at the same time. Alberich refers to them as the raw material from which a blade capable of slaying a Holy Beast, to be wielded by a Divine Knight, can be forged. By sacrificing their life, the Oz series sublimates into a weapon that is referred as the Sword of the End (終末の剣). It is the only blade that is capable of damaging the Holy Beasts of Aidios. Alberich requires this blade to unleash the curse contained within the corrupted Holy Beast sealed in the Gral of Erebos.
- stole the process for creating homunculi from the alchemists of Crossbell.
- provided the mages with the technology required for the Magic Knights during the Dark Ages.
- distributed experimental weapons to high-ranking jaegers to collect combat data.
- participated in Ouroboros' Thirteen Factories
- got closer to Epstein's top disciple.
- took advantage of Reinford Group, the continent's leading manufacturer of heavy machinery.
'OzXX is introduced in the second half of Trails into Reveries Infinite Corridor, where she discourages the party from following her deeper into the dungeon. OzXX is the Oz series' prototype, developed by the Gnomes through the technology stolen from the Crois family. OzXX appears as a young girl, strongly resembling KeA because of the similar technology used.
In the depths, she reveals that Elysium manifested her as receptacle for its manifestation of the Demiourgos, the Sept-Terrion of Mirage, which OzXX was trying to stop. Similarly, Demiourgos also tried to maintain her slumber. By getting manifested against her will, she became instable and she is stopped through a three-party battle. After the fight, she returns to her slumber. OzXX, released from her duty of suppressing the Sept-Terrion, also quietly vanishes, followed by the area itself.