In Pokémon Black and White, Marshal appears as a member of the Elite Four of Unova. He calls himself Alder's apprentice, though he is largely unaware of Alder's thoughts. He is first mentioned outside Twist Mountain when Alder says Cheren reminds him of Marshal due to the value he places on power. Post-game, Marshal appears in Victory Road before Cheren's rematch, at the cave exit of Victory Road.
Marshal is first seen in Nimbasa City, carrying an unconscious White after finding her unconscious underneath the Rondez-View Ferris Wheel. When Black sees Marshal with White, he assumes that Marshal attacked her and sends out his Pokémon to battle. After easily defeating Black's Pokémon, Marshal gives White to him and explains everything. As he leaves, Marshal tells Black to take White to a hospital. Afterward, Marshal arrives at the seabed, where he meets with Alder.
When Black and White arrive at the Battle Subway, they find Marshal and Alder battling each other. Despite Marshal seemingly gaining the upper hand, the battle ends in Alder's favor. The Mayor of Nimbasa City reveals that the battle between Marshal and Alder was part of a series of tests for Battle Subway before it opened to the public. Despite a lack of battling experience, White decides to take part in the next Battle Subway test. Later, Marshal finds Black sulking due to being jealous that White was chosen to test the Battle Subway and not him. Marshal tells Black to stop complaining and sends him off to help White catch her first Pokémon. After Black and White succeed in their mission to capture a Pokémon, Marshal notices that Black's newly caught Tirtouga used to belong to him before he released it a day earlier.
On Route 6, Marshal tries to convince Alder to not leave the Pokémon League, only for his pleas to be refused. They are approached by N, who challenges Alder to a Double Battle. Alder accepts N's challenge while Marshal referees the battle. In the end, Alder loses and eventually disappears, allowing Team Plasma to use his defeat as a means to justify their goals, which only increased the amount of released Pokémon and lowered the number of Pokémon League spectators.
At the Pokémon League, Marshal gathers with his fellow Elite Four members to make way for the tournament. Marshal, furious at how Team Plasma has used Alder's defeat to justify their goals, asks his allies to help join in the fight against them. Much to his disappointment, none of them agree with his wishes. The four then watch as spectators for the tournament before their battles can begin. Although the tournament is won by Black, the event is interrupted by Team Plasma, who attacks the stadium by surrounding it with N's Castle. The Elite Four travel on Shauntal's Golurk to try and confront N at the top of the castle, but they are attacked by Hood Man, who uses Tornadus, Thundurus, and Landorus against them to try and figure out how to activate the three Pokémon's Therian Formes. After gaining sufficient information, Hood Man escaped, taking the Pokémon with him.
This listing is of Marshal's known Pokémon in the Pokémon Adventures manga.
Throh is Marshal's first known Pokémon. He was used to battle Black's Nite in Nimbasa City, where he easily won.
Sawk is Marshal's second known Pokémon. It was used to battle Black's Brav in Nimbasa City, where it easily won. During Team Plasma's attack on the League, Marshal used Sawk to battle Landorus. With the power of Caitlin's Gothitelle's Telekinesis, Sawk and Marshal were able to float in the air.
Marshal had owned a Tirtouga sometime before arriving in Nimbasa City. Because of his hard-to-control nature, he had released him the day before meeting Black and White. He was later captured by Black and named Costa.