Ok, first, spaces between sentences!
I'm sorry for snapping, but it is very hard to read when everything is running together like that.
Sticking with grammar for now, it needs a lot of work.
Not only could it use a pass through a text editor, but the composition needs some spit and polish.
The sentences are mostly disjointed, singular statements of facts that normally begin with "Xanna this" or "Xanna that" and don't really have any flow between them.
Still, that's a skill that most people need to work on and you have mentioned that you're new to this.
Now, on to the character himself...
His back-story is... actually pretty decent, if a bit cliche.
He's a humanoid weapon developed in a lab, who got out and was reared in an orphanage.
I especially like how you took the time to tie in a lot of his personality traits with his upbringing.
But... there is a HUGE problem with this character, his "Lava Elemental" parentage...
Elementals in Felarya are spirits that form a physical body out of their "element".
While they do apparently hybridize with Fairies, it's generally considered that's more magical then genetic in nature.
Really, I don't see how it is possible to splice Human and Elemental D.N.A.
Though, if you want to keep the "Fire Monster" angle of Xanna's profile, I do have a pretty easy solution.
Simply replace his "Lava Elemental" origins with a more flesh-and-blood Fire Creature, like the Salamanders from the Wiki.
That way, he can have his innate Flame powers and probably a monstrous form, but people won't question them because they come from something that has D.N.A. you could splice with.
Finally, I has a few questions I'd like to ask.
Like, where was Xanna created and/or raised anyways?
If he was created on Felarya, then it begets questions of who created him and why they haven't bothered to track him down?
As well, if the orphanage he was raised in is on Felarya, why does his fondness for Nekos come from playing with cats when he could have easily just interacted with a member of that race in the first place?
Anyways, I hope this has been helpful!