[@Adorabadass], Honestly, all of our 18-19 year olds are already skirting the lines between caravan-able and military age- the original idea was for most characters to be in the 16-17 year range. At the 20+ year mark, he'd definitely be sent off to war.

First things first: "Wears a helmet with a retractible face mask. No one has yet seen his face and head in the caravan." 
Why is this a thing? So many heroes and villians try to use a perpetual mask trope to appear mysterious and cool- but the vast majority are not very successful. Oh, also, is Thorn human?

Your character's personality, is somwhat sociopathic, extremely aggressive yet compassionate- with what appears to be little capacity to work in groups- which as a group RP will probably be a regular thing. Conflict and turmoil is good for the development of RP characters, but I don't necessarily want a wild-card doing whatever the hell he feels like doing on a given day. 

I find it interesting that your character's sister went from the daughter of a playwright to a demon hunter. When did the children of artisans gain the physical capacity to join and survive the grueling life of a demon hunter? The experiments performed on him seems so randomly thrown in, and is never mentioned again, but coincidentally gives him a lot of magical powers. Also, your background- Thorn has lost not one, but two sets of parental figureheads.

Regarding your skills and abilities.. Thats a really big list. Also with extensive weapons skills [i]and[/i] the capacity to perform potent magic. My section on skills state: "Magic is a rare talent and is difficult to master. If you intend on making your character a user of many weapons- chances are s/he won't be a master of magic.", nevermind the other multitude of performance and gathering skills Thorn is handy in. The "experiments" performed on him is frankly a poor explanation for why he suddenly has powerful magics.

Why does Thorn's armor resist dark magic in particular? and why can it detect the difference between his dark magic and someone elses?

This character is frankly, in my opinion, quite overpowered and bordering on mary/gary-sue territory.