As the 1-year anniversary of Honkai: Star Rail approaches, developers continue to introduce new characters, worlds, and unique gameplay mechanics to enrich the game experience. With each update, players may consider which existing or upcoming characters are worth investing in to enhance their team synergy and gameplay strategies. In the version 2.1 update, two new 5-star characters, Acheron and Aventurine, were introduced, along with the 4-star character Gallagher. Each character offers unique abilities and roles, making the choice between them dependent on individual player preferences and team compositions. While rerun banners alongside them may influence choices due to similarity in roles, such as Acheron with Jingliu for both DPS roles or Aventurine and Luocha for sustain roles, players should consider several aspects to make informed decisions.