Dmitri Yuriev is a major villain in the Xenosaga franchise, though he really only becomes antagonistic during Xenosaga Episode III.
Background
Dmitri Yuriev was the first human to come into contact with U-DO through the transfer experiment. He saw the same thing that everyone else who contacted U-DO had seen: The end of the world. This left him with an incredible fear and this fear led him to use the Relics of God to ascend to the Upper Domain. He also founded the Yuriev Institute and created URTV's, Designer Children with the purpose of defeating U-DO, including the four Variant URTV's Rubedo (Jr.), Albedo, Citrine, and Nigredo (Gaignun Kukai). After fourteen years of training, Dmitri used the URTV's to heal Sakura Mizrahi, who was suffering from a mental disorder due to an obstruction in her neural pathways. Unfortunately, their efforts failed and Sakura died, which led to Joachim Mizrahi creating MOMO.
At some point during the Miltian Conflict, Dmitri was shot and killed by Nigredo. However, instead of leaving, Dmitri's spirit entered Nigredo's body and awakened again after fourteen years. From then, he resumes his plans to defeat U-DO using Nigredo's body. He reunites with Citrine and starts working with Dr. Sellers.
Some time after Shion summons Abel's Ark, Dmitri takes control of the Durandal while Shion and her friends are at the Merkabah. Dmitri and his soldiers kill nearly everyone on the Durandal. Two people he didn't kill were Mary and Shelly Godwin, who he used to get the Arbiter Code to access the Zohar Emulators. Then, with the Zohar Emulators in his hands, he crashed the Durandal into Abel's Ark. He later used the Zohar Emulators to awaken the Original Zohar, which is then absorbed by Omega Res Novae to make it transform. After the party fights Dmitri, he then fuses himself with Omega, causing it to transform again, this time into Omega Metempsychosis. After the party defeats Omega Metempsychosis, Dmitri separates from Omega. Dmitri then meets his end when Jr., Albedo, and Gaignun form a Spiritual Link around Dmitri. Originally, Albedo planned for Gaignun's consciousness to be placed into Jr.'s body. However, Gaignun had different ideas and instead forced Albedo's consciousness into Jr.'s body. Gaignun and Dmitri then both meet their ends.
Trivia
- Dmitri, while not a URTV, is a Designer Child himself.
- Dmitri has existed for much longer than any normal human being.