Supreme King's Scorching Fist of Death is a close-range blast using yellow Shinsoo, claimed to be a legendary technique by Urek Mazino. Even without being used at anywhere near full power, it was still strong enough to severely injure a person of Baam's level; granted, it was being used by one of the most powerful inhabitants of the Tower.
Notes and Trivia
First Emperor had his own version of this technique called, "First Emperor's Scorching Fist of Death". However he never had a chance to use it in the series.
After clashing with Urek Mazino, Baam learned to use the technique. However, he doesn't like to use it because of the embarrassing name, according to the author's afterword.
The Hanja are an educated guess by ThCmpny translator GoDai. SIU did not reveal them.