In the pulps, at least, The Shadow posed as millionaire playboy Lamont Cranston as the real Cranston spent most of his time abroad. By his own rare admission, The Shadow's real name was "Kent Allard".
In Doc Savage: His Apocalyptic Life, The Shadow's baptismal names were revealed as Allard Kent Rassendyll, and his parents as Ralph Rassendyll and Rhoda Delagardie. In Tarzan Alive, Philip José Farmer had suggested that G-8, The Spider and The Shadow were all the same person, but in Doc Savage he retracted this theory and made G-8 and The Spider the brother and half-brother of The Shadow, respectively.
In his Chronology of Shadows (an early version of which is available online), eminent pulp scholar Rick Lai provides an alternative parentage for Kent Allard, arguing that Kent Allard was actually the son of L'Ombre, a mysterious character who features in the novel The Phantom of the Opera, and a man called Theophraste Lupin, the father of Arsene Lupin. This is also the state of affairs in the French Wold Newton Universe. However, in his article "The Insane Captain Wentworth" (in his book Daring Adventurers), Mr. Lai asserts that L'Ombre was a member of the Rassendyll family herself, making Kent Allard a cousin of G-8.