Iris.

Iris debuts in BW001 swinging from tree branches on her way out of the Village of Dragons, where she trained from childhood as a future Dragon Master. Her partner is Axew, perpetually peeking from her hair. She joins Ash because she finds him interesting (and a kid) and stays because Cilan's connoisseurship gives the trio an unusual dynamic. Her tonal opposite to Cilan's pacing makes the BW trio feel different from the prior groupings; Iris's tree-climbing physicality and Cilan's tea-tasting deliberation balance Ash's headfirst impulsiveness.

Wins the Junior Cup early; ranks high at the Vertress Conference (Unova League); declines to enter the Pokémon World Tournament in BW for plot reasons. Departs in BW144 to seek out additional Dragon-type mentorship. The Journeys-era reveal that she has become Champion of Unova (during the World Coronation Series) was one of Best Wishes' most-celebrated callback payoffs; the show had foreshadowed it across multiple episodes without ever stating it explicitly.