India, Dec. 3 -- The story of Abdul Qadir Mumin charts a trajectory that has become disturbingly familiar in the global evolution of jihadist militancy: a soft-spoken preacher in a Western capital who transforms into the architect of a resurgent extremist network thousands of miles away.

Yet Mumin's path is distinct in one critical respect. At a time when theIslamic State's so-called caliphate had been militarily dismantled in Iraq and Syria, he managed to carve out a new frontline for the organisation in one of the world's most fragile regions-northern Somalia. From the windswept caves of Puntland, Mumin now leads a branch ofISISthat intelligence agencies consider one of the movement's most adaptive and resilient offshoots.

His rise ha...