The Deepest Purple Fleshfang is a dragon mentioned in the beginning of How to Ride a Dragon's Storm.
No description of information is given about the Deepest Purple Fleshfang. The dragon or its oil at least must be purple, due to its name. Because the author always capitalizes dragon species names, Deepest Purple Fleshfang, is its complete name, rather than "Deepest Purple" merely being a descriptor. Its oils are purple in color, so it is possible this dragon is colored purple as well.
Oil from this dragon is purple in color and is an alternative to Blubberwing oil in keeping a swimmer warm in frigid waters. Madguts the Murderous uses Deepest Purple Fleshfang oil as part of a ruse to disqualify Stoick the Vast and Big-Boobied Bertha from the Inter Tribal Swimming Competition.
- "Madguts can't help but notice that you're wearing that old-fashioned BLUBBERWING FAT ... It doesn't keep out the cold half as well as the Deepest Purple Fleshfang Oil that Madguts is wearing ... You put this on, and you're never cold again."