mamahaha no tsurego ga moto kano datta
A light novel series written by Kamishiro Kyousuke (紙城 境介) and illustrated by Takayaki (たかやKi). The English title is My Stepmom's Daughter Is My Ex.
The manga adaptation launched in April 2019 and is drawn by Kusakabe Rei.
An anime adaptation by Project No.9 began airing in July 2022.