Origin
Rachel MacGregor was a young blind girl whom was seemingly orphaned at a young age and came into the care of Miles von Crof, an former Nazi, whom adopted the persona of Mycroft, a so-called psyhic detective, in order for him to stay hidden from the authorities. Rachel had no knowledge of how evil Mycroft really was.
Creation
Rachel MacGregor was created by Jim Steranko and first appeared in Nick Fury, Agent of SHIELD Vol.1 issue 3 (1968).
Major Story Arcs
Meeting Nick Fury
Being Impersinated
Many years later, the son of Nick Fury, Nick Fury Jr. came into contact with someone whom stated to be the grown-up Rachel macGregor, but this turned out to be a Hydra agent in discuise named Frankie Noble.