I feel conflicted posting because my comic isn't quite ripe yet, but I also don't want this awesome thread to die.
So uhh, yap. Enjoy some "coming soon" characters I guess? XD
(left) Amber and (right) Skye of Pest Caravan (Fantasy, Sci-fi Comic)
I guess I go about designing characters by thinking of the world first, then creating the species that inhabit it. In the mythic world of Pest Caravan, traditional fantasy job classes are instead species that evolved with specific traits to suit the job class they're based on. Concept wise, it was a good enough start to try roughing out the different species and to see how close I could get to the class with only using natural laws. Magic doesn't exist in this world, but the scientific equivalent does.
So Skye's Bard species design was the easiest. If you need the ultimate singers in the animal kingdom, you can't go wrong with birds. I specifically chose a bearded vulture as a base for his character, because the animal behaves extremely similar to Skye. Bearded vultures' calls are nothing but a low raspy squeak despite being an imposing bird. They also cunningly feed off the bones of other animals by breaking them on hard stones. Skye is just as much a scavenger, living on the lowest rungs of society, and even though he is a member of the Bard species, he has an utter disdain for singing. Also, bearded vultures come with built in eyebrows that are perfect for emoting!
Amber's design was a little tougher, as she was a Pyromancer species. When nothing natural exists that can summon and wield fire, you have to think outside the box. Originally, I considered making her look very human as I was afraid of making too many creatures main characters. Ultimately, it got scrapped because it made absolutely no sense with the narrative.
So, with this creature design, I started with the base elements of what a pyromancer job class can do. I knew firstly the creature had to resist fire, and would probably be thick skinned or armored. After picking out some armor plated animals I liked, I went on to think how the fire could be made (without magically summoning it), and came up with friction plus accelerant chemical plus flammable oil (for sustainability of the flame). So if the animal were a mammal, you could produce a flammable oil sweat, have retractable quills or finger tips coated in an accelerant, and have the skin be rough enough surface to entice a good spark.
And oh jeez, doing that for all the classes was quite the challenge, but I wanted a fantasy world that didn't have your standard fair elves, dwarves, and orcs. As much as I love reading stories about them, I really had fun designing something new by treating a fantasy setting like science fiction. 
@sarrowsmith10 I guess to quickly answer your other questions:
Honestly, you could flip the genders of all the characters, and it wouldn't change the story a bit. All characters are intentionally androgynous, and gender really isn't a factor in this world. Somehow sexisim never took off, but speciesism and racism? That's another thing entirely.
For Amber, she's basically a child, and I thought it would be interesting to have a large ogre-like species not be a hulking brute adult. It plays into a story quite a bit actually. For Skye, he's at the age of finally understanding how the world works and coming to terms with it.
No one of the main cast have parents that are dead actually. Unless you count the Necromancers, but that's cheating really.
Skye ended up with Amber for reasons other than death or abandonment. 
Edit: Made some corrections and added sketches.
