The Imposter Candle was a neighbor of the former supervillain The Candle. He was a teenager whose father had died of cancer (due to being a smoker) earlier in life, leaving the boy to be raised by his mother. The Candle took up residence next door under the alias "Mr. McCandle", and often helped around his neighbor's house with maintenance issues. He seems to have become something of a father figure to the boy.
Before he died, The Candle gave his neighbor a letter, which he asked the boy to open only after his death. Following the Candle's funeral, the boy opened the letter and discovered that it contained details of how to find the Candle's melting ray, how to get fuel for it using the Thrifty Nickel, and expressing a wish that it be donated to science.
Instead of following this noble plan, the boy assuming the identity of the Candle (complete with overcoat, Wayfarer sunglasses, and red scarf) and robbed Klebbs Fine Jewels. The boy sold the jewels to a fence, then followed what he believed to be an ad in the Thrifty Nickel for Balthorium G.
Unfortunately for him, the ad was a trap laid by Guy Goddard, and the Imposter Candle was apprehended by the Middleman. He was taken to Middleman HQ and questioned in the Interrogation Room, where he broke down and told his interrogators about the last days of The Candle and his own crime spree. He was nearly beaten by Goddard, who thought he was lying, but the Middleman intervened at the last moment.
The Imposter Candle was not seen again, which suggests he was either released or turned over to police custody.