Shinzon was created in 2348 after a Romulan agent named Manathas, present at the wedding of Starfleet officers Beverly Howard and Jack Crusher, managed to acquire genetic material from Picard and three other Starfleet captains. This was part of Praetor Narviat's program of clandestine infiltration of the Federation—the same program that led to the capture and examination of the Soong-type android known as B-4.
Shinzon was initially raised and trained for a mission to replace Picard, and was genetically altered to be triggered to age rapidly once he'd reached his early thirties, skipping three decades of his life so as to resemble his progenitor more closely. Early in life, he was diagnosed with a rare Human disease that Picard had also suffered as a child.
Exile on Remus
"I was born in the darkness, moulded by it. I didn't see the light until I was already a man, by then it was nothing to me but blinding!"
By the early 2360s, however, a new faction achieved prominence in the Imperial Senate. While Narviat retained his post as praetor, the faction terminated the infiltration program, and the young Shinzon was exiled to the dilithium mines of Remus.
There, he was raised by the Reman known as Vkruk, who renamed him "Shinzon," the Reman word for "twilight," because of the child's fascination with the line that separates the light from the dark. From Vkruk, Shinzon learned of the strength of personality necessary to survive, and grew to hate both the Romulans and the Humans, despite his fascination with his origins.
He did not see a sun for ten years.
By the 2370s, however, Shinzon and Vkruk were both drafted into the Romulan Imperial Fleet to serve, along with numerous other Remans, as shock troops—little more than cannon fodder. Shinzon's tactical genius soon manifested itself, however, leading to his ascension amongst the Remans. Shinzon ended up leading twelve successful engagements during the Dominion War, rising to such prominence within the Imperial Fleet that the Tal Shiar charged his Reman troops with the re-capture from the Dominion and destruction of a Tal Shiar base located within the Neutral Zone. The base had been the site of research into banned thalaron radiation weapons and was in imminent danger of capture by a Federation-Klingon task force; this would have exposed the research, an unacceptable outcome. While the Tal Shiar had intended to kill Shinzon afterwards, Shinzon captured the warbird that would have incinerated himself and his troops before the engagement; winning the base, he discovered the weapon and the long-forgotten B-4, and used this information to gain for himself command of his own warbird.
Rise to Power
During the years between the end of the Dominion War and his coup, Shinzon steadily gained allies within the Imperial Fleet and Romulan government in preparation for his takeover. Shinzon courted leadership in the Imperial Fleet, including Commanders Donatra and Suran, and senators such as Tal'Aura, winning them with promises of a war against the Federation in the post-war environment. Meanwhile, at a secret base, Shinzon gained a personal starship, the Scimitar, a massive new warbird with advanced cloaking and disruptor technologies that he had outfitted with a thalaron weapon.
His ascension to power had not gone unnoticed; as a now-prominent military leader, he was seen as a leader for the Remans, and talk of civil war loomed; still, few suspected his plans. By October, the pieces were in place.
During a full session of the Imperial Senate in the Hall of State, Tal'Aura left in the senatorial chambers a small thalaron weapon that activated, killing Praetor Hiren, the Senate, and all other forms of organic life within the chambers. Ki Baratan erupted in riots; moving in with the Imperial Fleet's support, Shinzon declared himself the new praetor. (Star Trek Nemesis, Taking Wing.) However, he knew that the time of his intended aging was fast approaching; without the advanced aging, which he was unable himself to trigger, Shinzon's only means of survival lay with a complete blood transfusion from Jean-Luc Picard, his "father." To achieve this, Shinzon engaged in an elaborate ploy, luring Picard to Romulus with promises of a new peace with the Federation with the intention of kidnapping Picard to gain tactical information on Starfleet deployments before killing him with the transfusion. From there, Shinzon intended to travel aboard the Scimitar to Earth, where, consumed by his hatred of Humanity, he would destroy all life on Earth with his ship-based thalaron weapon before betraying the Romulans and doing the same to them.
In the course of this plot, however, Shinzon underestimated his adversaries, who realized that he had planted B-4 aboard Picard's ship, the USS Enterprise-E, to facilitate the abduction; he also became sexually obsessed with Picard's senior counselor, Commander Deanna Troi of Betazed, who was able to use a telepathic link that Shinzon had forced upon her to thwart the Scimitar 's cloak. In a battle to destroy the Enterprise before Picard and his crew could join a Federation fleet, Shinzon's ship was heavily damaged; meanwhile, Donatra, realizing that Shinzon had become genocidal, betrayed him, bringing her flagship, the IRW Valdore and another warbird to join the Enterprise in battle. Eventually, Shinzon was defeated and the Scimitar destroyed by Lieutenant Commander Data, who was killed in the line of duty. Shinzon himself was killed by Picard in hand-to-hand combat, proclaiming that their destiny was now complete.
In spite of his short life and the brief duration of his coup—the assassination of the Senate and Shinzon's death occurred within three days of one another—the enormity of Shinzon's impact cannot be overstated. The Romulan Star Empire was left in chaos and the Imperial Fleet was fractured, both in a power vacuum. Tal'Aura later claimed praetorship, but this was opposed by several different factions, including Donatra's faction of the Imperial Fleet. His coup also led to the liberation of the Remans and a state of near-civil war between the Romulans and Remans and between the Romulans themselves for nearly a year afterwards. Eventually, the Remans were relocated to the planet Klorgat VII and Tal'Aura consolidated her praetorship; however, Donatra's faction of the Imperial Fleet remained rogue until December of 2380 when, in orbit of Achernar Prime, Donatra proclaimed the existence of the Imperial Romulan State and her own status as its empress. The Romulan Star Empire was reduced from a galactic power to two states, risking the spread of advanced Romulan technology to politically unstable worlds and utterly destabilizing the Alpha and Beta Quadrants. Despite age and mental disturbance, Shinzon surely left a mark on galactic history that will not soon be forgotten.
The wreckage of the Scimitar, from his failed coup d'état, became a spatial anomaly with the unofficial name
In January of 2382, agents for the Order of Omega went back in time just prior to the explosion to retrieve Shinzon’s remains. His remains were beamed aboard a Romulan warbird. An unnamed Romulan Doctor close to the House Xeral ordered Shinzon to be immediately cryogenically frozen in order to preserve his brain function. Shinzon was then healed with a complete blood transfusion from an Augment prisoner. This prisoner was Princeps Jean-Luc Picard, Commanding Officer oft he the Earthfleet Starship Illustrious.
In one alternate timeline, there was no Dominion War to take Shinzon away from Remus. He would have died in the dilithium mines, were it not for another regime change in the Romulan Star Empire in the mid 2370s. The Continuing Committee revisited Narviat's plan to infiltrate the Federation,and came up with a variant strategy. To that end, they had Shinzon liberated from the Reman mines, and Tal Shiar geneticists managed to reverse the cellular damage. Shinzon began training as a Tal Shiar assassin, eventually alongside of other members of his cloning creche.
Shinzon in the Star Wars universe:
(working on it. ;))