"I can compare 2019 with 2012, when they were beginning, organizing themselves," Major General Sirwan Barzani, a Kurdish Peshmerga commander, told the BBC.
The controversial history of the Barzani family has taken a series of major blows lately, and its Kurdish rivals blame the current leader for recent chaos.
Kurdish fighters are sieging the largest Iraqi city under ISIS control.
Iraqi prime minister Haider al-Abadi says Mosul's fall would mark the defeat of ISIS in Iraq.
"U.S. weapons are supposed to come from Baghdad, but they're not coming," said the general. "All of our weapons are Russian, and we bought them on our own."
The serviceman is the third military member to die fighting ISIS in Iraq.
Kurdish forces launched Operation Sinjar against ISIS early Thursday morning.
Some of the prisoners have spoken about their ordeal after the dramatic rescue operation.
The peshmerga have emerged as a key partner in the U.S.-led coalition in its campaign to demobilise ISIS.
A new video features deaf-mute brothers who claim to be traffic wardens in militant regime