The leader of ISIS, one Abu Bakr al-Baghdadi, was seriously injured and incapacitated in a drone attack a couple of months ago that took the life of his close aide. After the attack Baghdadi's second in command, the ill-fated Abu Alaa al-Afri, took the reins. Now there's another job opening since al-Afri and dozens of other ISIS jihadis were evidently reduced to ash recently in a drone attack on a mosque in the Iraqi city of Tal Afar.
An article in the British Daily Mail explains the reasons for the "churn" in the ISIS leadership:
Figures from February showed allied airstrikes, including those carried out by British warplanes, had killed more than 6,000 fighters since September. The figure included more than half of the militants on the IS ruling council.And it looks like it's going to continue to grow smaller.
Among the dead jihadists was Abu Muslim al-Turkmani, a former Iraqi army lieutenant colonel considered Baghdadi’s number two and the most senior ISIS militant in Iraq.
His death and that of as many as nine others on the 18-man leadership council forced Baghdadi to promote local warlords to the status of regional commanders, as his inner circle of trusted advisers and battle-hardened loyalists became increasingly small.