Here is a comprehensive, logical overview of what happens t…

Here is a comprehensive, logical overview of what happens to all the remaining major and notable supporting characters from Seasons 1–3 (and related movies/novels) of Sound! Euphonium during the timeline of the alternate Season 4 (*Resonance Beyond the Score*). This picks up immediately after high-school graduation (post-Season 3/Nationals gold achievement) and covers the characters’ transition into university or early adult life, while staying consistent with the dramatic events of Season 4: Reina’s confession/rejection/secret pregnancy/return, Kumiko-Mayu’s intense fusion, the university concert band, and the broader themes of lingering band bonds, romantic complications, and life after the “final note.”
I’ve grouped them for clarity, focusing on those not covered in the previous response (Kumiko, Reina, Mayu, Shuuichi, Asuka, Natsuki, Yuuko, Hazuki, Midori, Taki, and baby Lumina/Jack). Developments remain true to each character’s established personality, instrument/role, and arc while extending them naturally into adulthood.
### Kumiko’s Close Friends & Kitauji Quartet Complements
- Hazuki Katou (Tuba, cheerful and straightforward):
Hazuki graduates and fulfills her long-stated dream by becoming a daycare teacher (working with young children, much like her warm, energetic personality). She stays in the local area and occasionally visits the university concert band for casual rehearsals or reunions. At the graduation after-party, she cheers loudly for Kumiko and Mayu’s surprise intimate makeup moment, laughing it off as “finally!” without judgment. Hazuki remains a grounding, optimistic friend who checks in on Kumiko via texts, offering simple advice like “Just do what makes your heart go doki-doki!” She represents the “normal life after band” path—happy, low-drama, and still musically involved on the side.
- Sapphire “Midori” Kawashima (Contrabass, bubbly and cute-obsessed):
Midori also graduates and finds work in a creative field (perhaps event planning or a music-related retail/job that lets her stay around instruments). She remains close with Hazuki and attends university band events as an alumna. At the after-party, she squeals with delight at Kumiko and Mayu’s public affection, declaring it “the cutest duet ever!” Midori continues her cheerful support from the sidelines, sometimes joining casual jam sessions. Her arc emphasizes staying true to her energetic, supportive self without the intense pressure of competitive band life.
### Other Third-Year Graduates (Kumiko’s Classmates)
- Haruka Ogasawara (Former band president, low brass):
Haruka graduates with a sense of quiet relief after her leadership struggles. She pursues a more stable, non-music university path (possibly business or education) and steps back from intense band involvement. She appears briefly at the graduation party, offering mature advice to the group and reflecting on how far the band has come. Haruka watches Kumiko-Mayu’s closeness with gentle amusement, happy that the “next generation” is finding their own harmony.
- Kaori Nakaseko (Trumpet, gentle and romantic):
Kaori graduates and continues music casually while studying something practical. She remains the kind-hearted senpai figure, sending encouraging messages to the university group. At the after-party, she notices the emotional undercurrents (Reina’s hidden pain, Kumiko’s shifting affections) and offers soft, empathetic words. Kaori’s presence underscores lingering band friendships without deep entanglement in the new romantic dramas.
### Second-Year Characters (Now Entering University or Continuing Locally)
- Mizore Yoroizuka (Oboe, intense and socially anxious):
Mizore graduates (or advances if timeline-adjusted) and pursues music conservatory or university studies focused on oboe performance. She remains deeply passionate about music but struggles with the same interpersonal anxieties. She attends occasional university band guest sessions and interacts awkwardly but warmly with the group. Mizore observes Kumiko and Mayu’s fusion with quiet fascination, perhaps seeing parallels to her own intense emotional investments. Her arc stays introspective, with music as her primary emotional outlet.
- Nozomi Kasaki (Trumpet or related brass, from earlier seasons):
Nozomi has already graduated earlier but makes cameo appearances at reunions or the after-party. She has moved on to work or further studies, offering nostalgic encouragement to the younger alumni. She reacts to the dramatic shifts (especially Reina’s return with a baby) with surprise but supportive maturity.
- Tomoe Kabe (Trumpet, anime-original addition):
Tomoe graduates and pursues a balanced life—perhaps university with part-time music. She appears at the party as a lively supporter, cheering the Kumiko-Mayu moment and staying connected through the alumni network.
- Tsubame Kamaya (Percussion, energetic second-year):
Tsubame advances or graduates around this time and joins the univer…