With his distinctive red beard, al Shishani has become one of the most recognisable faces of a group now notorious for extreme brutality in its pursuit of an Islamic state across large swathes of Iraq and Syria.
But his father remembers a young man who was never particularly religious, but who always wanted to be a soldier.
Born in the remote Pankisi Gorge in Northern Georgia, an area once seen as a stronghold for Chechen militants, his real name is Tarkhan Batirashvili.
When he was younger, he worked as a shepherd boy in the hills above the gorge, where he reportedly first met Chechen fighters, crossing the Caucasus mountains to fight Russian forces across the border.
"He was a very good boy, very well behaved," Timur Batirashvili remembers.
"Always very intelligent, very nice, he hated when people lied.
"Do you know what I think now? I didn’t know my son. I didn’t know him at all."
Tarkhan joined the Georgian army and served in the Russia-Georgia war in 2008.
His father said he seemed happy, that he had found his place in the world.
By Katie Stallard, Moscow Correspondent, in Pankisi, Georgia @ Sky News