Board Thread:Legitimate Canon Questions/@comment-25333461-20150702155620/@comment-84.195.61.177-20150714135718

He's a salamander. Hellhound doesn't fit the description that accurately.

Salamanders are immune to fire, can put themselves or others on fire, and can also remove fire of themselves and others, and can if needed be heal instantly. That probably explains why he didn't die of the fire, because he was immune and put it out himself. Other than that they are also very loyal, courageous and protective of their close ones.