Mir and Muichiro, Zenitsu, Inosuke, and Tanjiro found a pretty crystal at a thrift store until Mir and Mui were shunned w/ a bright light and turned into kids

Tanjiro: "oh.my.god."

Inosuke: "..huh—"

Zenitsu: ".. Ho-ly–"

Mir looks up at them and holds Mui's haori cause, well theyr kids and they have no memory of Tan, Zen, and Ino