just a few thoguths but wheres his weapon for killing a dragon? kinda seems like uve got a guy who rock climbs, he doesnt scream owt dragon slayer to me, maybe have him use parts of slayed dragons as weopons and armor etc. just try make him look a little bit more individual. if hes a dragon slayer what year is this in? what type of person would slay a dragon? what are his motives for killing them? money or just to free the land becos then u cud protray him as a hero or as a person who cares about no1 but himself. make his equipment look important and individual to him, symbols, cool buckles, cool war paint, tattos, awsome scar (since hes probably faced many b4) just really try add some spark to your design. hope this helps 
edit: maybe some cool burns since dragons breath fire. lik his hair really different avin it in a quiff