Hopefully tomorrow. I need to think of one.
And ok an example of him using his magic.
Umm ok lets say Natsu uses Roar of the Thunder Dragon. To negate the attack he would need to use a similar amount of magic power used to use Roar of the Thunder Dragon (which if memory serves is A LOT, maybe too much for him.)
But spells like Fairy Law he cannot negate or block. Also his magic breaks apart the attack over distance, so the closer the attack the more likely he cannot stop it. Basically I just wanted a (near) invincible shield, but there are a few weaknesses.

One: Distance. As I said, the closer you are the more magic power he would have to use to stop it quicker. Time might also be a factor.
Two: Spells of high magical power or difficulty he cannot block, he simply doesn't have the power required to do so.
Three: He must concentrate on stopping the attack. If his concentration is broken, the magic won't work and it can actually fuel the spell.
Four: If his magic fails to negate the spell, then it will make the spell bigger.

Do these weaknesses seem reasonable enough? I mean we only get one magic so he can't actually attack, but I wanted him to be at least able to protect himself. Also where are the hiders?
And yes that does look better. I shall fix it now.
EDIT: Never mind. Found the hiders.
Also I will make a back-story soon. Need to find one, might just spice up an older character of mine from another RP if I can't find of one.