Sangwoos mom was dead since the first chapter. In the manhwa it showed that she had forced herself into the knife and killed herself so sangwoo put her in his wall not wanting her to leave making her stuck dead and rotting, it probably did smell but the house was also old too. Did that help or do you need me to explain it more?
I mean, sure but I'm a bit reluctant to believe the corpse stayed like that for 4/5 years. Anyway, thanks. Also, check out this theory that I've found. https://www.google.com/amp/s/heytrashprince.tumblr.com/post/183486656385/when-did-sangwoo-really-kill-his-mother-chapter/amp
Can someone please explain what exactly happened to Sangwoo's mother's corpse? How did it not get rotten and smell? Or was she not dead since the first chapter??!!