Shiro Buta Kizoku Desu Ga Zense No Kioku Ga Haeta Node Hiyoko Na Otōto Sodatemasu Manga !!better!! -

The protagonist, Regulus Fenrir Ainsworth , was once the reviled first son of a marquis family—overweight, arrogant, and stupid. After dying from overeating at a banquet, he reincarnates? No, he simply remembers : a previous life as Tanaka Kaito , a hardworking Japanese office worker who loved cooking, budgeting, and caring for his younger siblings.

Waking up at age 7, Regulus is horrified at the monster he was destined to become. More urgently, he finds his 4-year-old brother —a frail, silent boy nicknamed “Hiyoko” (chick) by servants for his yellow hair and trembling demeanor—locked in a dark storage room, bruised and forgotten by their cold noble parents. The protagonist, Regulus Fenrir Ainsworth , was once

Using his past-life knowledge, Regulus makes a solemn vow: He’ll lose the “white pig” weight through proper nutrition and exercise, outmaneuver the scheming adults who want him dead, and—most importantly—raise Luciel into a strong, kind, and confident young man. From cooking homemade meals and teaching basic math to confronting abusive tutors and planting secret vegetable gardens, Regulus builds a quiet revolution inside the gilded cage of nobility. Waking up at age 7, Regulus is horrified

But as Luciel begins to smile and speak more, their parents grow suspicious. The engagement to a cruel noble girl looms. And someone from Regulus’s original “bad future” timeline seems to have noticed the changes… From cooking homemade meals and teaching basic math

A deceptively gentle manga about the hardest kind of courage: changing yourself to save someone who has no reason to trust you. Highly recommended for readers who like their isekai low-fantasy, high-emotion, and heavy on the domestic fluff earned through pain.

Here’s a solid, detailed write-up for the manga:

Fantasy, Slice of Life, Reincarnation/Isekai, Family Drama, Comedy, Redemption