SUMMARY
The non-state conflict between the High Council of Afghanistan Islamic Emirate and IS on the one side, and the Taleban on the other stems from a leadership conflict in August 2015. Following the announcement of Taleban leader Mullah Omar's death, and the realization that the central leadership of the Taleban had kept his death a secret for two years, several commanders started to oppose the newly elected Mullah Mansour as the leader of the Taleban, refusing to pledge allegiance to him.
The High Council of Afghanistan Islamic Emirate questioned the transparency of the process in which Mansour was elected, saying that he "got himself elected in a meeting of his own people", and that he was not the legitimate leader.
High Council leader Mullah Mohammad Rasool Akhund and his deputy Mullah Mansoor Dadullah were two of the main commanders fighting the Taleban, in Hirat and Zabul provinces respectively.
In Zabul, the High Council forces were joined by Uzbek militants who were part of the Khorasan Province of the Islamic State (IS). The Uzbeks belonged to IMU (Islamic Movement of Uzbekistan) who had previously fought together with the Taleban, but officially joined IS in August 2015. The High Council of Afghanistan Islamic Emirate also fought the Taleban without the involvement of IS (see the non-state conflict between the High Council of the Afghanistan Islamic Emirate - Taleban) and IS fought the Taleban in several other areas of Afghanistan, independent of the High Council (see the non-state conflict between IS - Taleban).
Mansoor Dadullah was killed in the clashes in Zabul in November 2015.
The non-state conflict between the High Council of Afghanistan Islamic Emirate and IS on the one side and the Taleban on the other is first included in UCDP data in 2015. In November that year, clashes in Zabul province, Afghanistan, resulted in over 50 battle-related deaths.