Isami Tatewaki (帯刀 勇 Tatewaki Isami) is a boy from Tokyo, Japan, who unwittingly reactivated the Swordbot Samurai Team using a sacred mirror from his grandfather's kendo dojo. He is known to be a skilled swordsman, though he can sometimes be overconfident. His strong sense of justice leads him to face two Predacons head on in order to avert the destruction of his neighborhood, and interacts with his Legendisc to allow the Samurai team to combine!
The Predacons Budora and Gaidora attacked Isami's grandfather's kendo dojo just as he and his grandfather were praying before their dojo's sacred mirror. When it became clear that the Predacons were targeting the sacred mirror, he grabbed the disk and made a run for it. Unfortunately, he realized that the more he ran from them, the more of his neighborhood the Predacons would destroy in their pursuit. So, stopping in a park, he confronted the Predacons, telling them to leave his town alone. When the Predacons decided to threaten some children playing nearby instead, his courage and sense of justice activated the Legendisc he was carrying and summoned the Swordbot Samurai Team. The Legendisc later somehow responded to him to allow the three Swordbot Samurai Team warriors to combine, and feeling that they owed him a debt of gratitude, the three warriors asked Isami to join them in hunting down the reactivated Predacons! He got a phone call from his friend Tobio Fūma, who had also teamed up with a trio of Autobots, the Swordbot Shinobi Team.
Isami was startled to discover that his Autobot friends had constructed a base beneath the dojo. Once Optimus Prime had briefed both him and Tobio on the Legendiscs' power, the two boys resolved to help track down the two missing discs. Time travel on the part of the Predacons resulted in parts of Tokyo disappearing, so Isami and the Samurai Team used the Legendisc to travel back in time, when they encountered Musashi Miyamoto who turned out have had his Legendisc stolen by the Predacons. They managed to track down Budora and Bakudora and retrieve the disc, though following the inevitable battle, Isami lost it before they returned to the present.
They had a second chance to retrieve the disc when Isami and the Autobots went back in time again and encountered a young Ryōma Sakamoto, whom Isami challenged to a duel over the disc. When Budora and Bakudora turned up to claim the disc, Isami's determination inspired Ryōma to turn over the disc, allowing Isami to use its powers to let the Autobots combine, though the disc was again lost when they returned to present day. Though Isami was disheartened by two failures, Kenzan told him not to give up. On their next trip to the past, they encountered Benkei Musashibō, whom Isami was able to defeat in combat, resulting in Benkei mistaking Isami for the savior he was seeking. When Gaidora and Judora claimed Benkei's disc, the man's tenacity in trying to get the disc back inspired Isami, who retrieved the disc and allowed the Autobots to triumph, though they again returned to the present without the disc.
It was quickly realized that battling the Predacons was causing the other Legendiscs to time jump, a safeguard intended to protect the discs. On their next time slip to the past, Isami and the Samurai Team found themselves at the home of master swordsman Bokuden Tsukahara. Isami was able to impress Bokuden with his wisdom, and the swordsman presented him with the Legendisc. On returning to present day with the disc, the team was confronted by Gaidora and Judora, who had both gained increased size and power from Dragotron. Though the Autobots were able to defeat them, Dragotron himself arrived and turned the tables, at which point Optimus Prime arrived in a new form to help. Depart! Optimus Exprime!
After a brief fight, Dragotron grabbed Isami and left with his Predacons, heading to Mount Fuji. There Dragotron absorbed both Isami and Tobio into himself, granting him the power of all five Legendiscs and allowing him to start Cyberforming the mountain. Though the Autobots were no match for the powered-up Dragotron, Isami and Tobio were able to use the courage in their hearts to reject his evil and expel themselves from his body. Unfortunately Dragotron still dominated the Autobots in battle, however Isami and Tobio had copied the Legendiscs' power into their hearts of justice, and glowing with power, they absorbed into Kenzan and Gekisoumaru, allowing them to combine with Optimus and defeat Dragotron. After the Predacons were sealed away, they all stood around and contemplated the restored Mount Fuji.
- Isami's name, 勇, means "courage" or "heroism", which suits him. His last name "帯刀" also means "one who carries a sword" or "sword-carrying", so his name effectively translates to "Sword-carrying hero"! Tatewaki is also a name associated with samurai.