Arise

Raises a squad of shadow soldiers from the ground around you. Small circles open at your feet, smoke rises, and twice as many soldiers as the spell's level climb out to guard you: they follow you, fight whatever attacks you, and join whatever you attack. They crumble back into smoke when their time runs out, and casting again replaces the squad.

No mob teaches this spell. The System hands it out to those who complete the right daily quest.