Pakistani militant Asim Umar has been handed a very tough job.

Thrust into the limelight after being named leader of al-Qaida's newly created South Asian wing, he has been entrusted with reviving the network's fortunes at a time when Islamic State is generating grisly headlines and luring recruits.

Little is known about the man whose thinking was shaped in radicalized seminaries and madrassas of Pakistan and who will now spearhead al-Qaida's activities from Afghanistan to Myanmar. His current whereabouts are also a mystery.