Honjitsu no Shinomiya-ke

Mari, a beautiful young woman, becomes the new lady of the Shinomiya household. She hopes the boys will accept her as their new stepmother! Despite Mari's concerns, the five brothers were generally cooperative, except for the fourth son, Katsushiro, who seems clearly disgusted... Thus begins a delightful daily life story filled with family love and lucky-pervert moments!

(Source: Kadokawa, translated)