Sol Harriman (Earth-616)

The Blue Diamond was a Nazi spy that was active during World War II who was stationed in New York City. In the spring of 1943, he had learned of the successful test of Professor Philo Baker's Puff-Gun and sought to steal the device for himself. Sending a fake telegram to the Bakers' apartment telling them that their son was in the hospital, the Blue Diamond's men then stole the weapon.

The Human Torch and Toro was called to help find the stolen weapon. Finding a bug in the Barker's room, they made up a story about how the Puff-Gun required a special infrared filter in order to work and that it was placed in a safety deposit box in the Merchants Bank.

Falling for this, the Blue Diamond and his men broke into the bank and clashed with the Human Torch and Toro. Realizing that there was no filter, the Blue Diamond took Toro as a hostage and fled the scene. Toro was able to send off a signal flare, leading the Torch to the Blue Diamond's hideout.

The Blue Diamond was defeated when he fired the Puff-Gun indoors. Missing the Human Torch, it struck the ceiling of the room they were in causing debris to fall on him. He was then easily captured and the Puff-Gun recovered.^[2]

The Blue Diamond's subsequent fate is unknown.

The Blue Diamond wore a fire-proof cloak.

The Blue Diamond briefly wielded the Puff-Gun, an experimental weapon whose shot dissolved its targets into a puff of smoke.

Real name revealed in the Marvel Mystery Handbook 70th Anniversary Special #1.