The grown-up Suika was designed as a complex fusion of three elements:
her original “Suika-ness,” Senku’s influence, and Kohaku’s influence.
Suika, her own-like elements:
Her hairstyle carries over the essence of her old watermelon helmet.
Although she no longer wears the helmet, she keeps it around her neck like a pair of goggles — it even has lenses, adding a functional aspect.
Her hair itself retains a botanical, “watermelon-like” shape, with leafy and vine-like parts that evoke her old look.
Senku-like elements:
As an older Suika who has learned from both Senku and Kohaku, she reflects what she learned — and her feelings toward them — through her outfit.
She carries a utility belt similar to Senku’s, filled with scientific tools.
She also wrote the equation of relativity herself, in her own handwriting — round and soft — the same script seen on Senku’s new cloak.
However, her belt design is an original creation of her own, showing that Suika is intelligent and inventive, not someone who merely imitates others.
Kohaku-like elements:
The shield and weapon she carries on her back are a direct homage to Kohaku’s signature gear.
Her footwear has also changed to wooden sandals with heels, similar to Kohaku’s.
However, instead of simple sandals, she also wears leather shoes — a nod to Senku’s footwear.
Even the shorter skirt is a style inspired by Kohaku.