Aqua Admin Matt/Manga/PA/First Matt

Matt debuts in the. He first appears as a alongside Shelly and. The three were tasked with stealing the heart component of the Submarine Explorer 1 from Mr. Stone. When unintentionally thwarted their original plan to discreetly kidnap Mr. Stone, the three switched to a new plan and directly attacked Mr. Stone in public and stole the component. Sapphire, Gabby, and Ty chased after the three and eventually arrived in Petalburg Woods, where they were attacked by Matt, Shelly, and Amber in order to ensure that no witnesses to their crime would be left alive. With the help of Mr. Stone's, Sapphire manages to escape, but is unable to retrieve the heart component.

Later, Matt, Shelly, and Amber are given promotions from Archie due to their good work. With this promotion, they are given the title Subleaders of the Sea Scheme, or SSS for short. Archie is quick to remind his subordinates that they are still in trouble for leaving the witnesses alive.

The SSS travel to Mt. Chimney so that they can increase the sea level by stopping the volcano's activity. By pretending to be on the side of good, Team Aqua tricks Professor Cozmo into providing a special Meteorite that can stop Mt. Chimney. When they overhear Gym Leader Flannery talking about Sapphire, the SSS attack her in order to get information about their earlier opponent. Flannery is held captive by Matt so that he may lure Sapphire into a trap and kill her while the others finish their jobs. With the use of his Pokémon, Matt nearly drowns Sapphire and Flannery in the cable car, but Sapphire manages to drain the car and defeat Matt. Having won, Sapphire rushes over to stop Team Aqua, but Amber manages to stall her long enough for Shelly to kill Mt. Chimney. With their plan succeeded, Team Aqua escapes and takes Professor Cozmo with them.

When Team Magma and Team Aqua briefly join forces to journey to the bottom of the sea in the Submarine Explorer 1. Matt expresses excitement at the prospect of going to the Seafloor Cavern. When Archie questions if Matt would be able to go, Matt assures his leader that his injuries are almost healed. Archie then proceeds to have his knock Matt away. Matt is told that for his defeat at Mt. Chimney, he will be left behind and Amber will go in his place.

When and  are awakened, the Gym Leaders split into groups in an attempt to stop both Pokémon. In order to prevent their opponents from keeping Kyogre from advancing, each of the SSS splits up and attacks a Gym Leader. Matt faces Winona, and with his, he manages to prevent her from listening to her commands. Despite this, Matt struggles to fight Winona and is eventually defeated after Winona knocks him into the water as she goes to defend Flannery from Shelly. As he struggles to stay afloat, Matt begs Shelly to help him as she runs away after her battle ended. Shelly refuses and tells Matt to save himself.

In the Chuang Yi translation, he is known as Ark.

Pokémon
Matt owns the following Pokémon in the Pokémon Adventures manga.