Yui Kodai

A flat, unreadable expression is Yui's default. Her cerulean eyes run slightly narrow, her skin is fair, her frame athletic, and her black hair sits in a bob reaching her shoulders, the bangs swept toward her right with shorter pieces falling over her eyes.

Her hero costume runs red: a plain bodysuit trimmed white at the collar, a matching V crossing her chest and circling her upper arms, and a white skirt cut short, fronted by a red panel that dips to echo the neckline. White vambraces accented in yellow cover her forearms, and she wears a red cap carrying white U-shapes along each side, two yellow dots up top, a white strap behind, and a fin-shaped piece of metal at the back.

A grey oval gem rides her collar. A belt with a yellow buckle and a set of shoulder straps carry small pouches, each stocked with the nuts, bolts, and assorted metal scraps she likes to feed her Quirk. Her design descends from an early prototype for Ochaco Uraraka that also fed into Mt. Lady, and the crest on her cap recalls Ultraseven's Eye Slugger, a fitting nod for a size-changing power.

Yui talks little and shows less, enough that some classmates file her under kūdere. The reserve is not moodiness. Happiness gets a "Mm!" out of her, and tomatoes, her favorite food, get a louder "MM!" She looks out for her class as well: during the forest training camp she watched over Juzo Honenuki and Ibara Shiozaki once Mustard's gas had knocked them cold.

Size lets Yui alter the dimensions of any inanimate object she touches, and pressing her fingertips together returns it to normal.

She is no direct fighter and does not need to be. Enlarging objects hands her allies extra weaponry, and small or shrunken items thrown ahead of time become ambushes the instant she expands them. The Joint Training Battle's last round showed both the ceiling and the limit of that approach: Reiko Yanagi moved Yui's enlarged objects telekinetically while Nirengeki Shoda amplified the force behind them, a chain that still ended with Ochaco Uraraka taking Yui out quickly. In the Final War the same partnership mattered more. Yui and Reiko fed Mt. Lady a supply of enlarged levitating weapons so the giant Lurker could subdue a reawakened Gigantomachia, and they kept it up until All For One finally overwhelmed the heroes.