This OC is kind of two ponies but share the same body. I'll explain in a bit.

Mighty Dagger
Age: early 20's
Gender: Male
Species: Unicorn
Sexuality: Straight
Appearance: He has a medium length white mane that spikes up in the back and a spiky white tail, has grey fur coat and a muscular figure. He wears a wide variety of different color coats from dark blue to light green to golden, he really likes coats. He has a black bandanna that always covers his mouth. His eyes are green but are stone cold and almost lifeless.

Personality/info: He comes off as cold and distant to others and tries to avoid small talk, but there's a reason for this. He's actually a lone assassin who works for different clients and carries out different assassinations. They can range from quiet and deadly to loud and brutal. He can use anything as a weapon, but his favorite tool is his flame-designed dagger. It's basically a combat knife with a fire decal on it. During assassinations he can be very serious and very focused, but during head on fights is a different story. He displays a crazed, snarky, violent and rather arrogant persona when fighting a foe head on. He has a strong sense of justice and fights for what he believes is right, trying to make Equestria a better place. So he's not all for the money or some kind of revenge. But he has done some things in which earned him a bounty on his head. He's taken down gang leaders, corrupted Canterlot citizens, diamond dogs, vamponies, and sometimes rogue manticores. He also has a deep fear of dragons and lizards. However, there is a different side to him.

Rusty Nail
Age: Early 20's
Gender: Male
Species: Unicorn
Sexuality: Straight.
Appearance: Similar to Might Dagger's only he likes to wear tool belts and wears his bandanna around his neck, revealing his mouth. His green eyes are the same, only they have more emotion in them.

Personality/info: Rusty is a friendly and outgoing young stallion. He's a young carpenter who's trying to find a place he can call home. He takes his work seriously and loves to hang around with others. He's the kind of guy you can always depend on and he'll always be happy to make a desk for you, and is usually working with a smile on his face. However, he does have a dark side that he tries to hide from others. He has split personality disorder, with a deadly and twisted second personality named "Might Dagger". He's fully aware of this second persona and tries to hide it from others, claiming that he doesn't want to hurt anyone. He doesn't know how this happened, he just woke up one day surrounded by bloodied knives. He doesn't know how to feel about this, on one hand there's a personality who's trying to make the world a better place, but on the other he's doing it by killing others, the thing Rusty absolutely detests. He's also fascinated and interested in dragons. He moves from town to town to try to live a normal life and find his very special somepony. Somepony who has similar interests, somepony to hold, and will always be willing to help him, especially with his condition.

Hello? Is anyone here?

It's a shame no one responded to this. This is an interesting OC with an interesting problem. More interesting due to the possible answers than the split personality itself, in my opinion. We've all seen that before after all.

The reason for the sudden appearance of Mighty Dagger could be many things. He could have been a curse put upon Nail for some reason or another, or perhaps an example of what happens if Discord doesn't remove his "opposition" hex thing after the victim is apparently reharmonized. Another possibility is that Rusty Nail himself brought Dagger into the world through some great mental upheaval. This would be the more straightforward split personality route, whereby Rusty Nail was unaware that he truly held certain opinions and feelings within him due to a lack of introspection, and they came out all at once in the form of Mighty Dagger. It'll be kind of a tough character to explain, but not at all impossible.

4771719 You really think so? And Thanks, I'm glad someone finally responded to this OC

4781863 Yeah, he's/they're interesting enough :) They both look developed and, of course, have an interesting dilemma. - another possibility that comes to mind is that Mighty Dagger is actually the original "Rusty Nail" and was somehow sealed away in the latter's subconscious while a replacement, non-murderous personality was crafted over the top. That would certainly serve as an awesome twist.

And I don't really know why no one commented on this, since it was... there wasn't really anything wrong with how you presented them. I posted a thread a few days ago (Sparkfree) which I made really, really long. So people at least have an excuse for passing over that one. Oh well.