Responses
Touko, yoshiteru, kanata, and sumihiko in this chapter is great grandchildren of tanjirou x kanao and zenitsu x nezuko, so they're the third generation not 4-5... Touko refers to zenitsu as their great grandfather when yoshiteru read his journal (the title of the journal is "the legend of zenitsu" lol, the typing is kinda small so you probably missed it)

(๑•ㅂ•)و✧