Scorch is Named Enemy in Borderlands 2. They are located in the Frostburn Canyon region on the Planet Pandora. You encounter them during and after the side quest “Cult Following: False Idols” in the Frozen Ant Lake area and in the Raid on Digistruct Peak.
You can farm Scorch for the Hellfire as he is the dedicated loot source for this item. Scorch’s legendary item has a 10% drop chance.