Thunderbolt was a Bahdnesian "hex bolt" commanded by the uncostumed "mystery man" hero known as Johnny Thunder during World War II, who was a member of the Justice Society of America. After the war, Thunderbolt stuck with his master when he traveled to Tibet where he was born in order to find himself, only to return to the United States when the Chinese Communist army invaded that country. Thunder found Al Pratt working for Tex Thompson's campaign office as part of the Federal Bureau of Superheroes and, by using Thunderbolt to get Pratt's attention, got hired on as part of the politician's promotion team.
At a rally in Washington, D.C. in 1950 where all costumed superheroes were to appear by Presidential decree to show their loyalty, Joan Dale (Miss America) publicly exposed Tex Thompson as being the Ultra-Humanite and attempted to also expose Dynaman as being Adolf Hitler in Daniel Dunbar's body when the Ultra-Humanite had Robert Crane (Robotman) silence her by murdering her in public. After the subsequent exposure of Dynaman by Rex Tyler (Hourman), which resulted in his fighting the various superheroes gathered at the rally, Thunder commanded his Thunderbolt to kill Hourman, which made the Thunderbolt so confused as to where he would stand in both his personal ethics and his obedience to his master that he just totally departed from the scene, leaving Thunder completely on his own.
Thunderbolt possessed genie-like powers that his master Johnny Thunder could access for one hour. However, the Thunderbolt cannot make decisions of his own in regards to ambiguous commands given to him by his master.
- This version of the character is native to the JSA: The Golden Age series of stories.
- Appearances of Yz, the Thunderbolt (JSA: The Golden Age)
- 1 Images featuring Yz, the Thunderbolt (JSA: The Golden Age)
- Quotations by or about Yz, the Thunderbolt (JSA: The Golden Age)
- Character Gallery: Yz, the Thunderbolt (JSA: The Golden Age)