The narrative is driven by her genuine disbelief, annoyance, or "reaction" to his antics.
Huh?
In many anime and manga tropes, the younger brother is either a protective prodigy or a sweet, innocent tag-along. The "Uchi Otouto Maji" trend subverts this by presenting a brother who is frustratingly realistic or absurdly "hopeless." uchi otouto maji react to