The Yakuza's Guide to Babysitting manga volume 4 features story and art by Tsukiya.

Kirishima goes missing without a trace—so it’s up to Yaeka and Sugihara to find him. Though the incident that caused Yaeka's injury seems to have been settled, it still weighs heavily on Kirishima’s heart. But thanks to Yaeka and Sugihara, they might just be able to return to their peaceful everyday lives at last.