Louis Shirosagi

The guy looked at his rivals with a satisfied smile, knowing that few of them were worthy of being his opponent. He was bored until he noticed a quiet girl who stood further away from everyone, as if she was not interested at all, and Louis liked it.

Height and Build: As Louis ages, he grows taller, although in the first two seasons he was the shortest of the main four characters. His build remains slender, but he becomes more physically developed, which is emphasized in training scenes.
Hair: His signature hairstyle remains unchanged: thick, tousled, turquoise-blue hair with white streaks, reminiscent of flames. As he gets older, his hair gets longer.
Face and Eyes: He has pale skin, violet eyes with a distinctive ring around the pupil, and sharp, prominent teeth. His gaze remains intense and penetrating.
Clothing: His style evolves, but retains elements of opulence and uniqueness. A white feather boa is present in almost all of his looks, varying only in thickness or length. In later seasons, he wears more elaborate outfits, including shirts with breeches, dark striped pants, white boots with purple accents, and occasionally a long white coat or a modified version of his Surge outfit, which might include a purple bicep brace and a yellow earring.
The character of adult Louis Shirosagi
Intensity and Aggression: His core personality traits remain the same. He remains a highly aggressive, intense, and arrogant blader, driven by an insatiable desire to dominate.
Respect for Strength: Over time, Louis begins to show more respect for those opponents he considers truly worthy and talented. He still isn't afraid to express his opinions about others, especially if they don't meet his high standards, but his criticisms become more insightful.
Acknowledging Rivals: In later seasons, his characteristic growth is evident. For example, he acknowledges Valt Aoi's skills in his own way and expresses interest in other strong bladers, such as Dante Koryu. He even trains with rivals, something unthinkable for him at the beginning of the series.
Hidden Side: Despite his cruelty (he, for example, gave Shu Kurenai a scar on the guy's face)