Following the demise of the UBCS, Article 12 of Umbrella's Internal Emergency Procedures was enacted, and all materials and personnel still within the city were placed under the command of Colonel Sergei Vladimir. When it was discovered Delta Force had infiltrated Umbrella's facilities, Col. Vladimir prepared an SH-60B Seahawk for B.O.W. deployment. T-00, however, was dropped over the Raccoon Police Station with its own mission. It had two orders: first, to eliminate any police survivors, and second to locate the G-Virus.[excerpt 1] T-00 crashed through the roof of the 2F east passage, but by this point only three police officers were left.
The police station was soon after abandoned by survivors Leon S. Kennedy; Ada Wong; Claire Redfield and Sherry Birkin, and T-00, having spotted at least one within the station, began pursuing them into the sewers and, finally, into NEST. T-00 discovered Kennedy and Wong on level B4. In the ensuing fight, he seriously wounded Wong, but fell off a ledge after being shot in the face. Falling into molten metal, T-00 suffered serious burns but was able to climb out of the vat on level B8. Confronting a survivor, he mutated into his Super Tyrant form. With the help of Wong, who threw the survivor an FIM-92 Stinger, T-00 lost the fight and was destroyed.
Over the years T-00 has been given nicknames. The earliest nickname in official media was "Mr. X", which was chosen by Toy Biz for their 'Series 2' action figure (released May 1998) in lieu of a name provided by Capcom. The Pocket Books novel, Resident Evil: City of the Dead (released May 1999), has Claire Redfield pick "Mr. X" as a nickname from a list also including "Frankenstein's monster"; "Terminator" and "Dr. Evil". The same nickname was used in Resident Evil: The Official Comic Magazine #4 (published December 1998), wherein "Mr. X" was the actual name of the series, with duplicates of the original game's T-002 being "Tyrants". Capcom, however, did not acknowledge this nickname, and in the 2010 game, Resident Evil: The Darkside Chronicles, T-00 is instead nicknamed "Coated Bastard" (コート野郎), or "Trenchy" in the English dub.
In the original Resident Evil 2, once the T-00 is downed players will be able to pick up ammunition on certain occasions by examining his body. This only works in the story mode.
The inclusion of a fedora to the T-00's outfit in the remake was to emphasize its intended purpose for covert operations. The T-00 was also made physically shorter for the same purposes, as it now appears more human from a distance.
In the remake, the T-00 has a more tempered personality. During its pursuit of the player, it will frequently crack its neck and show subtle signs of irritation when presented with resistance or receiving damage. This temper is shown if the player shoots off his hat, causing him to charge for the player, instead of his usual walking pace. While in its Super Tyrant form, it will roar furiously at the player multiple times during their final encounter with it.
Some people theorized that there are two Tyrants in the 2019 remake, because of it dying early on in Claire's story after being impaled by G and re-appearing later on in Leon's story. However, the developers confirmed in an interview that there's only one Tyrant and that the stories are parallel to each other (which explains some things not adding up such as fighting G's first 3 forms twice, the Tyrant inconsistency and Annette dying twice, among other things). [excerpt 2]
On a hardcore difficulty 2 shots from Anti-tank weapon are needed instead of just 1 on standard difficulty in order to bring the Super tyrant down.
During it's concept stage, the T-00 was originally supposed to wield a large gun. This concept was passed onto the Nemesis-T Type.
T-00 originally only chased and followed the character used in the B Scenario and would not be seen entirely by the other character in the A Scenario.
Additionally, the T-00 would lose its coat after falling in a smelting pit. In Claire B, the Tyrant is chasing Sherry Birkin for the G-Virus within her pendant, allowing Claire to toss it into the smelting pot with the Tyrant joining the pendant shortly. In Leon B, Leon is cornered by the Tyrant and is rescued by Ada, who fires multiple shots to the Tyrant's face, eventually causing to fall into the pot, but it is able to wound Ada severely.
The T-00's final encounter would also be near the emergency train itself, obstructing the B Scenario's character from boarding the train after they finish connecting the plugs to open the railway's gate. Like the remake, the Tyrant would be blown to bits by a Rocket Launcher tossed in by Ada Wong.
↑Excerpt from biohazard archives (2nd ed.), p.189: 『命令に従う能力が向上しており、ラクーンシティでは「Ｇウィルス」回収命令に従って目標を追跡した。』.
↑Excerpt from PC Gamer Interview: There’s only one Tyrant. When designing the game, we wanted whichever scenario the player is currently in to be representative of the main story arc. You could say that each scenario could be considered a parallel world, which is why you see Tyrant appear multiple times.