Nothing is known of the mage known as Mango the Mighty before he first came to public attention in 1940.  In the summer of that year, a series of strange deaths plagued Boston, deaths in which the victims were appeared burned to death with no evidence of fire anywhere near them:  No smoke, no collateral burns, no scorch marks.  The police are mystified as is Doctor Fate, who has been observing their inquiries from the skies.   Fate resolves to seek our Inza Cramer to learn more as she is more immersed in  the mortal world than he.  Inza reveals that the deaths are all a series of wealthy individuals but the link between them is not clear.

As Inza and Fate converse, a cloud of Malaysian poisonous bats attack.  Fate ignites and seals the window to comfort Inza but a lament flame like those responsible for the murders hurdles toward the pair.  Fate captures in a magic grip and returns whence it came.  Realizing this is a chance to find its origins, Fate and Inza take flight in pursuit. They find a house on a desolate promontory up the coast and are accosted by more balls of flame.  Doctor Fate repels them and blasts open the door, only to be swarmed by legions of the undead that separate he and Inza.

While Fate struggles against the hordes, Inza is taken before the author of these acts, an adept who calls himself Mango the Mighty.  He shares that he sought resources to further his efforts and murdered the men who refused his attempts at extortion.  Binding Inza, he ignites more magical fire and leaves her to burn but her cries summon Fate who saves her.

Bent on a final resolution, Fate tracks Mango through his castle.  He finds the mage in a circle of bone, preparing a spell to allow him to slip between dimensions and escape.  Fate destroys the bones and directly attacks Mango physically, rendering the mage unconscious.  Realizing the mortal laws and prisons were no match for mystical dealings, Fate entraps Mango in the form of a small clay statue and instructs Inza to lock him in a ebony cabinet, preventing his escape and restoration (More Fun Comics #57).

Whether Mango ever returned in unknown.