Upon conquering the region of Sinjar in Wilāyat Nīnawā, the Islamic State faced a population of Yazidis, a pagan minority existent for ages in regions of Iraq and Shām. Their continual existence to this day is a matter that Muslims should question as they will be asked about it on Judgement Day.
Islamic State propaganda, quoted in Cheterian, Vicken (2019). "ISIS genocide against the Yazidis and mass violence in the Middle East". British Journal of Middle Eastern Studies: 1–13. DOI:10.1080/13530194.2019.1683718.