The third Mr. Fear was a classmate in law school of Matt Murdock's, Larry Cranston. He holds a grudge with Murdock and discovered his rival's dual identity as Daredevil which led him to become Mr. Fear.
Larry Cranston first appeared in Daredevil #88 by Gerry Conway and Gene Colan. He first appeared as Mr. Fear not long after in Daredevil #91 also by Conway and Colan.
Mr. Fear was believed dead for decades and briefly returned in Joe Kelly's run on Daredevil. He returned permanently under Ed Brubaker's pen. In the time that had past, a fourth Mr. Fear had emerged (Cranston's nephew Alan Fagan), and for a time there were two active Mr. Fears - particularly confusing as they both had active presence in books at the same time. Since then Cranston has died again and Fagan is the only Mr. Fear.
Major Story Arcs
Mr. Fear returned from his apparent death and made Daredevil's wife Milla Murdock loose complete touch with reality. Though Daredevil was able to get him captured, Mr. Fear was able to brainwash his guards so his stay would be as pleasant as possible. Daredevil could not harm him since he held the cure that could one day save his wife.
Powers and Abilities
Uses fear pheromone administered by gas pellets or occasionally by a syringe. This can cause insanity, and only he has the cure. It also causes one to be suspetible to his commands. His drugs can also control animals and cause hallucinations. Cranston was able to additionally create a drug that made him fearless. He also was an effective lawyer.