hi there! well i used to quite like houndour, but less so when it came to houndoom. The callous points on the body would make logical sense, having developed them as a thick outer shell to protect newborn pups. the other option is that they’re part of the dogs skeleton that grows outside the skin, seeing at the points on the back resemble a ribcage, at least in part. Its also a bit odd because houndor seems to have a bony section on its head that could be a skull, but it loses it upon evolution in favour of rams horns. If i were to draw them realistically, i would probably keep that part in, along with the horns and make them more ram like. 

And i think that’s, in general where I’d head, the sections are extra parts of the skeleton that form outside the body, attached to the inner ribcage (meaning no organs are vulnerable, we wouldn’t want that XD) And as they mature, the head crest develops into horns that are used for mating rituals, possibly even head butting or goring when agitated.

as a further note, being a fire type, i might suggest these ‘bones’ are also a way of the creature cooling itself when it becomes excessively warm, perhaps blood flows into them like a stegosaurus’ plates allowing for heat to escape?

in any case, thats where id personally go, but your idea about the tougher, armour like skin would work very well too, and serve the same functions  :) 

i use Photoshop cs3 and a wacom bamboo tablet :) im really glad you like my work!! :D and in terms of brushes, id say stick with the ones built in Photoshop for now and then branch out into other ones, its always good to learn the fundamental ones you can use before the special ones :) (at least, that’s how i think hahah!)

sorry this took me so long to reply! firstly, thank you! secondly, when i get the time, i may well draw voltorb, though theyll be similar to my magnemite versions i think. i had the idea that they were man-made pokemon used in the war to be mistaken for pokeballs. being that pokeballs would have been an expensive and rare thing, youd have to assume that someone would pick it up, and when they do? bang! :)