There’s not a lot of backstory to explain who the Ambassador of Death is including where he is an ambassador for. The only thing that is certain is that he is a Nazi sympathizer which is enough information to get boiled alive by the Flame.
References: [The Flame #8] [1942] [murders various south american leaders to create distrust with the U.S.; foiled and boiled alive by the Flame; “Fool! To think he could outwit me!”; ]
Metahuman Database 