Moritori Rex is a former Grandmaster of the Dark Legion and grandson of the infamous Dimitri. Moritori Rex found himself becoming a spy for the Dark Legion when he was mistaken for the Guardian Tobor and brought to the Brotherhood of Guardians' secret base Haven. For many years, Moritori Rex managed to pass himself off as Tobor until his true identity was revealed by Knuckles the Echidna. Following this, he rejoined his fellow Dark Legion members and served under Dimitri, who had taken command of the Legion. After the Dingo takeover of Angel Island, Moritori Rex was captured and studied by Dr. Finitevus and tossed into the Twilight Zone along with the rest of the surviving Brotherhood members when the mad scientist had completed his studies.
Following the death of his father Menniker, Moritori Rex assumed command of the Dark Legion. Although they were trapped in the confines of the Twilight Zone, Moritori Rex had found a way to spy on Mobius. Eventually, Moritori Rex created a device which allowed him to breach the dimensional barrier and return to Mobius. Though he led the Dark Legion in an all-out offensive against Echidnaopolis, the real reason for his attack was to lure in the Guardian Tobor. When he and Tobor were locked in mortal combat, Moritori Rex used the same device used to bring the Dark Legion out of the Twilight Zone to teleport them both to another part of the Floating Island. Once there, the two were buried under rubble. Tobor's father Hawking arrived on the scene, mistaking the severely wounded Moritori Rex as his son and brought him back to Haven.
Spy and Saboteur
How Moritori Rex was able to masquerade as Tobor is largely unknown, but he used it to his advantage. With the Brotherhood of Guardians believing him to be one of their own, and Tobor having left Angel Island out of shame for his failure, Moritori was in the perfect position to act as a spy for the Dark Legion and eventually destroy the Brotherhood from within. For many years, Moritori assumed the role of Tobor and worked alongside the Brotherhood while reporting back to the Dark Legion. Eventually however, his schemes were compromised when Tobor returned to Angel Island. Moritori managed to sabotage Haven's power generator and spy network long enough for Tobor to disappear from the scene, thus preventing his true identity from being discovered.
Not long after, Knuckles found himself transported into Haven, surrounded by his forefathers. Knowing Moritori Rex was an imposter, Knuckles played along until he was alone with him. Moritori Rex led Knuckles into the medical room, hoping to inject him with a toxin that would kill him. Before he got the chance however, Knuckles stopped him. The two fought in hand-to-hand combat until Moritori was forced to flee. Although Moritori was trapped in a locked-down room within Haven, he managed to teleport out to freedom. He left behind a banner for the Brotherhood saying "shinginta", which in ancient Echidna dialect means he promises they "will all make friends with death".
Reunited with the Legion
Following his escape from Haven, Moritori rejoined the Dark Legion. During the Legion's attempt to take over the High Council of Echidnaopolis by having their cyborg Benedict run in the elections, Moritori contributed to Dimitri's plans considerably. Prior to his escape of Haven, Moritori managed to secretly sabotage Haven's defenses, which allowed Dark Legion troopers to break in and capture Thunderhawk, Sojourner and Sabre, as well as take control of Haven. This prevented the Guardians from acting against Dimitri and the Dark Legion in their attempts to rig the election. However, the Legion failed to capture Knuckles' father Locke or Tobor's son Spectre, the latter of whom blinded Moritori, given cybernetic eyes after ambushing Spectre.
Some time later, after the Dark Legion's failure to rig Echidnaopolis' politics, they used their massive cruiser to fire the Quantum Beam which sent all life on Angel Island into another zone. Moritori Rex, equipped with a new set of eyes that looked astonishingly organic, was on board the cruiser and the helm, where he shared Lien-Da's sentiments that Julie-Su should have been left behind and banished to the alternate zone along with the others.
Some time later, Moritori Rex was captured by Dr. Finitevus along with the rest of the surviving Brotherhood. For months, Finitevus studied them in order to see how they were able to tap into the Chaos powers. Finitevus was also particularly interested in discovering how Moritori managed to pose as Tobor for so long without being discovered. When Finitevus completed his studies, he disposed of the Brotherhood and Moritori Rex into the Twilight Zone.
Moritori Rex is both devious and malicious. Willing to use any means at his disposal to win in a fight, even if it requires him to "fight dirty", Moritori will use it. He is loyal to the Dark Legion cause and willing to betray the Brotherhood without second thoughts to further the Legion's goals. Additionally, Moritori shared Kragok and Lien-Da's sentiments that Julie-Su was not part of their family, as she was the daughter of Luger with his second wife.
- Moritori's name is similar to the Latin word morituri, which means "those who are about to die" and the word rex means "king", thus his name is close to meaning "the king of those who are about to die."
- In a Q&A, when responding to a question regarding how Moritori Rex viewed his son Luger, writer Ian Flynn said: "In a word: dissatisfied. I don't think Rex outright hated his son; I think there was still a small, "human" part of him that felt at least a responsibility to acknowledge him. But I don't think he lingered on the news of his death. While Rex was busy scheming in the Primeverse, Luger achieved very little in terms of returning to Angel Island. I see Rex as being disappointed with Luger's apparent lack of drive or viciousness, which is why he turned his attention to the next generation."
- Kragok originally called Moritori his father in Knuckles the Echidna #18, though this was later retconned. In Sonic the Hedgehog #205 the reason for Kragok calling Moritori his father was explained as both Kragok and Lien-Da considering him their true father, due to their disappointment in their biological father.
- Moritori is one of the only Echidnas who still possesses original Dark Legion cybernetics-along with Spectre, Julie-Su, and Dimitri-having not had his removed by Enerjak.