She wakes one night to find her father forcing oil down her throat just as Goro used to drink it. Yui begins to develop acne and a bad temper, just like Goro. The restaurant enjoys a revival in popularity due to Goro being served to the patrons but, when the meat runs out, the customers stop coming back. The 'saturation level' also rises to 80%. Yui loses her ability to take pleasure in the sight of Mount Fuji after she starts to have a recurring nightmare in which it erupts grease, flooding their town. However, their father saves Yui by bashing Goro over the head with a frying pan, accidentally killing him he then gets rid of the body by serving Goro's flesh to the customers in his restaurant. He goes into an extreme psychosensitive rage and he screams he's going to kill everyone in revenge. Although she hesitates, he gets angry and he traps her, bursting loads of his zits on his face at once so that pus rains down onto her.

One day, Goro orders Yui to go out and buy more oil for him to drink when they run out. He is bullied at school because of his skin condition, which makes his already extremely violent temper worse. As he becomes a teenager, he develops extremely severe acne from the grease in the air, puberty, and his habit of drinking oil straight from the can. Yui's older brother, Goro, is a violent and abusive bully. Yui becomes sensitive to what she calls the 'saturation level' of grease in the air, which currently stands at 50%. The shop and restaurant are covered in oil and grease, and the air is constantly heavy with grease due to a lack of ventilation. Yui and her family live above the barbecue restaurant her father owns, in a town at the foot of Mount Fuji.

Chapter 5 of Voices in the Dark and Chapter 9 of Shiver (titled as Greased).

Junji ito collection shiver