Eiji Nagasumi/Partners

Tyrannomon


Eiji Nagasumi also owned four Tyrannomon, though currently only has three of them as one of them was killed by ModokiBetamon.

At some point, Eiji was hired to get a ModokiBetamon for Tomonori Ryusenji.

With Eiji having managed to track one down, he sends three of them to get it, with the three of them chasing it around the subway. Just as they were about to trap their prey in a corner, a subway train drives passed with the Tyrannomon having to get out of the way to avoid being run over. They continue to chase it, with it running into the nearby sewers. As they look for it, one of them is suddenly killed by a surprise attack from it. Eiji, who was eating in local restaurant in the real world whilst they were hunting, received a notification on his Digimon Dock that one of the three Tyrannomon had been killed and — not wanting to fail the mission since he needed the money — quickly replaces the defeated Tyrannomon with the fourth one.

They are eventually able to succeed in catching the ModokiBetamon.

Eiji had been given and a Digimon Linker as a reward for getting Tomonori the ModokiBetamon, and wanting to be able to raise Loogamon properly, he goes onto GriMM and asks for tips on raising dog-like Digimon. He receives a reply, with someone telling him to put his Digimon with other Digimon he owned as they will all play together and learn together. He doesn't bother to read the rest of the reply though, which states that dog Digimon have a social hierarchy and to discipline it first, and instead transfers his three Tyrannomon from his Digimon Dock to his Digimon Linker.

Loogamon, over the next few days, proceeds to make itself leader of the pack. The Tyrannomon fear it, and tremble in fear of the dog Digimon in the corner of their cage during feeding time. As Loogamon was the leader of the pack, it had first dibs on food, and it had even tried to eat one of the Tyrannomon.

When it came time for Eiji to do his mission to be allowed to join the Sons of Chaos as an undercover agent, he chooses not to take the Tyrannomon with him as he was worried they would be too weak for it and as such would die during the mission.

Shortly after Eiji completes the mission in Ninth Avenue, he sends out the three Tyrannomon to collect map data and estimate the population within it. After the Tyrannomon return, Loogamon tells Eiji to have them to continue to patrol the area, so as to make sure no one could invade its territory (as Loogamon had regained some of its memories and remembered Ninth Avenue belonged to it), with Eiji telling them to do just that. A siren blares, causing the Digimon of Ninth Avenue to flee, with Loogamon telling Eiji to recall the Tyrannomon. As Eiji questions it he looks into Loogamon's eyes, realizes it's serious, and does as he's told.

When Eiji comes up with a plan to defeat Leon Alexander's, he decides to trick Leon into going to a floating island of garbage data and has the Tyrannomon hide on it. Unlike in their previous head to head battle, which lost, Loogarmon would use the flames of its Howling Burner to hide and upon  putting the flames out with its own attacks is surprised when Loogarmon had just been stood there doing nothing. This shock lasts long enough for Loogarmon to launch a counter attack at Boutmon, and before it can even do anything, is attacked from three separate directions from a sneak attack by the three Tyrannomon. It takes the brunt of the four separate attacks, with Leon confused as to how Boutmon hadn't picked up on them being there. Boutmon states it couldn't due the amount of junk data that was there, and that they had fallen right into Eiji's trap. Boutmon is able to shrug off the flames, as Eiji yells out about how he's going to defeat Leon even if he has to play sneaky to do so. As their attacks clash, Boutmon is able to overpower Loogarmon's flames and get in direct hits against its lower levelled opponent — but is unable to get many of them in as the Tyrannomon's distant attacks are able to distract Boutmon long enough to allow Loogarmon to distance itself. Realizing he wasn't going to win against four opponents who were just trying to wear them down and win in a long drawn out battle Leon decides to have Boutmon digivolve to Kazuchimon. Seeing the Tyrannomon terrified of the Mega level enemy, Eiji recalls them to his Digimon Linker.

Attacks
 * Fire Breath: Breathes out intense flames and burns the enemy.