Alright, this looks to be a pretty good app, but I'm still going to check it over to make sure it's not bad. Few things, we don't really use a number to determine age here, the 'Stallion' part is just fine by itself. I dunno if they'll look at that and say to take it off. Second, Equestria has no real military outside of the Royal Guard. That being said, your pony is a "Free Knight". I don't know what a "Free Knight" is, but it seems to be some sort of militaric position, and the only real military in FiM is the Royal Guard. Third, your English is a bit off and it's hard to really tell what you're trying to get across at times. The second sentence is a little confusing, as you use "have" instead of "has" and leave words out at some parts of the sentence, "some visible near" should be "there are some visible near", and I have no clue what "somehow old" is supposed to mean, nevertheless figure out how it ties into the sentence. Fourth, a lot of the stuff in your bio is a bit out-of-universe here. You say he ran away as a foal, but foals are babies. He'd have to be at least a colt in order to runaway. You explain that a "Free Knight" is just a different title for "Mercenary", but I'm pretty sure that mercenaries don't fit into FiM. If you want some sort of militaric character I'd suggest doing a Royal Guard or even a Town Guard, I'm pretty sure the towns need some protection.