I like dragons and reptiles so yeah~ ///// they're humanoid which are also dragon descendants... their population is quite low due to genetic, partner selection and various other factors. 

Notes:

• A pair of horns of various sizes and shapes, some might had more than 1 pair of horns though
• Some had curvy shaped hair strands under their horns while some don't. (I forgot what's the reason I added that...)
• Cold-blooded, body temperature regulated by their own flame
• Some scales under the area of their eyes
• Black sclera (Some, not all)
• Skins near palm area and feet are tough and hard, non-retractable claws. 
• Lizard/ dragon-like tail with various length and 2 variety of flamed tail and non-flamed tail. Tail are covered with scales on top and tough leather skin at bottom
• Flamed tail individuals are treated as higher ranked in society despite they're weaker compared to individuals without flame. The flame could not be extinguished for more than 24 hours for individuals that born with it. 
• Most royalties had flamed tail thus why they treated that as a symbolism for the rich/higher ranked officers.
• Individuals without tail flame are stronger and could produce more flame from their breath or palm. The flame on palm is necessary to keep themselves warm when temperature gets too low.
• Other people called them Devourer because when angered their flame becomes extremely hot and could burn up to 1600 degree (Which is dangerous as it might boil their blood and destroy body systems and organs). Their tough scales on arm serve as insulator at some point, some individuals don't have scales or little scales though.
• When they're with people they're familiar or comfortable with, the flame would actually feel warm and not harmful even when touched by non-Devourers. 

Added on 25th Oct:

• Devourers are actually wise and calm despite their scary look and rumours about their temper. They often looked pissed or not amused though LOL
• Average lifespan of a devourer is 700~800 years.
• Most Devourers love to dress fancy and neat, they cared about their appearance quite a lot. 
• Devourers' dragon form generally are more powerful but more sluggish compared to their human form.
• Devourers without energy to retain humanoid form would revert to their origin form. There are 2 groups of Devourers where 1 believed that the origin form is true and natural aesthetic of their kin while the other group prefer to stay in their humanoid form as a more pleasing choice. 
• Despite being fire-related species, Devourers actually don't mind going near water bodies as long as their flames don't get extinguished for more than 24 hours.
• They had superior sense of direction. It's rare for them to lost their ways on adventures and such. 
• Devourer's scales are great material to make into armors or vaults, when melted by a Devourer's flame the scales turn into molten state, their toughness could be on par with diamonds when cooled and solidified. 
• Loyal and keep their promise at all costs unlike other dragon kins. Thus, they're often being taken advantage of and some had been descaled at very cruel ways or deceived (Thanks puwi for the feelz switch here, yeah ) which is why they don't trust people easily. 
• Their population is quite low as they're very picky about their partner and their genetic pools doesn't merge well with non-dragon or non-reptile species. 
• They can actually hide their horns and tail if they wanted to, sometimes to avoid being hunted or being spotted. 

7th Nov 2015:

• They had thin, semi-transparent skin around their chest in dragon form, the areas are often protected by thin plate and linings of metal. Human call that area fire chamber as the chamber glows of colour of their flames (diff devourer might have different flame colour, this does not affect how hot their flame is though). It is also where the Devourer's heart is.
• The chamber simplified into tattoo-like markings around their chest in human form. 
• Devourers are wary and sensitive when people attempted to touch their chest area. 

Future base for the devs' dragon form: