Description
Bronius is one of Team Plasma's Seven Sages, high-ranking members assembled by Ghetsis to advance the organization's goals. Ghetsis specifically tasked him with propagating Team Plasma's ideology to the public, advocating for Pokémon liberation from human ownership. This duty involved overseeing operations like the kidnapping of Pokémon in Castelia City, including Bianca's Litwick, using his Amoonguss. He established a hideout directly opposite the Castelia City Gym, deeming the location ironically fitting despite its rapid discovery.

During the events of Pokémon Black and White, Bronius appeared with Ghetsis, Rood, and several Grunts at the Castelia City hideout, departing soon after the player arrived. Later, he and the other Sages (excluding Ghetsis) positioned themselves at N's Castle to block the player's path to N. The Unova Gym Leaders confronted and defeated them, forcing the Sages to allow the player passage. Following Ghetsis's defeat, Bronius relocated to Chargestone Cave. There, he provided the player with TM69 (Rock Polish) and reflected on Pokémon's loyalty to their Trainers, even when injured. He expressed uncertainty about N's understanding of this dedication and condemned those who mistreated Pokémon. Looker subsequently arrested him at this location.

In Pokémon Black 2 and White 2, Bronius and Ryoku were sighted within the Castelia Sewers. International Police members Blake and Looker pursued them after reports of Team Plasma stealing a man's Pokémon. Blake apprehended both sages during a sewer confrontation. Despite capture, Bronius and Ryoku remained confident, asserting their arrest served as a diversion for Team Plasma's larger objectives, signaled by a sudden chilling presence.

Within the anime adaptation Pokémon Generations, Bronius appeared briefly in "The Uprising." He stood among the other Sages as N's Castle emerged near the Unova Pokémon League. Collectively, the Sages discussed fate, justice, and superiority, with one declaring the absence of "two sons in the sky" or "two sides over the people." They anticipated Ghetsis's arrival and proclaimed Unova's impending fall to Team Plasma.

Bronius is known to quote philosophical texts, notably reciting a line from the Tao Te Ching at N's Castle in the games. His name derives from the Arabic word "sumra," meaning "brownness" or "tan," reflecting a naming convention shared with the other Sages (excluding Ghetsis) whose names reference colors.