Dragoon appearance question

Hi.

I'm Keir. I am a newbie here, making my first character and my imagination has run away with a big purple dinosaur. (No. That is not my character concept.)

Deacon Naerduïl Starchild, cleric of Gaia, son of a Diamond Dragon and a Quinarian virgin sacrifice by a band of misguided goblins on "Monster Island", is considered a mad prophet & cultist by his own people, who have expelled him from several cities indefinitely for his revolutionary ideals concerning indentured servitude... blah... blah...

While I respect the idea of the dragon within showing through your actions, I would really like to create a sense of alien being to the character I am creating.

So, my first question is... Can I use draconic features to show the heritage of my Dragoon classed character?
Maybe tie it into the unfinished paragon skill: Spirit of the Dragon.
I have contacts that I can use as a Quinarian that will match well with my chosen Dragon-type, but I am hoping for a little more. I would like my elf to have fangs. (I could see myself building a scaly arm with claws, but I need to know if I should even go there.)

The Big Deuce: Can I use a unicorn horn as my phokus? I have a clever story for that too, but FOIG.

Or maybe a Namierra with pink and purple stripes and a big axe? Named... CHESHIRAX! (of Thundera!)

So dragons mating with mortals is a thing that happened when they existed on Arawyn, which they haven't in ages. For over a thousand years the dragons have just been a legend to most people.

That being said, there are certainly options for you to accomplish what you want in appearance in the form of runes in game. These are highly sought after items that enhance your character, in this case with changes to your appearance. Unfortunately that means you can't simply start with them.

The idea behind dragoons are that they descend from the mortals who long ago mated with dragons, and manifest their abilities usually through combat or study under another dragoon.

Lastly in regards to caster focus, only the listed materials in the rulebook can be used to make one. So even if you were to somehow get a unicorn horn, it would not necessarily qualify to be made into an armament like a caster focus. Additionally I can personally say that unicorns are such rare a revered creatures that possessing a unicorn horn is nearly unheard of.

I hadn't spotted the part about dragons disappearing a thousand years ago. Still for an elf that isn't so far back, especially if dragon blood extends the already long life expectancy. Maybe it was his grand-mother all of those years ago. Or even great grand mother. Perhaps there is a Starchild family legacy that he is living up to or mangling horribly with the Quinarian people.

But learning this is exactly why I asked. I am not trying to get away with anything or change the world (at this point), I am trying to fit my ideas in the framework that exists.

I will continue to grow my backstory to match better, but I am hooked on the theme so far. I will look up the Runes you spoke of to get a better understanding of how they work. I also hope to figure out starting wealth and purchases.

I think I understand what you said about in game "materials" to be use to make the phokus and I totally get that a unicorn horn would not be a common item or even a tasteful one, I just like to play with mystery and mistaken perceptions because my character will otherwise seem too straight forward. Considering that I was planning on saying "Charlie. Wake up, Charlie." before wielding it, I should probably move on to the next concept.

Thank you for your knowledge and encouragement!