You have a good base, but there is some room to definitely grow. It looks like a person, attire wise Sophi is there (however not in the face or build), and there are things that need cleaning up such as her sword. Ashlotte's pretty good, but also loses some of the characters facial features and tone (her forehead to nose is a tad off for a person as well). So just clean up some of the line work (most of it is good), but put some focus on the faces. I know you're going for the anime angle, but even as limiting as anime is perceived, you still have a lot of options with a face to still have your own take on a predesigned character and have it transfer. They would be fine if they were you're own character, but they had an identity to portray and outside the accessories they don't. Even still they're a bit on the standard anime face with no individuality among other characters spare the bod they're attached to.
Another thing is, what is the picture of. Is it just a character? Is something happening? Does the pose or shapes present an attitude to express the character deeper? SC is a combat game and characters have origins as well as a few expressions featured in the game that shed light on personality. Bring that to the table by putting them in a pose or action. Maybe Sophi is wandering in search of Cas, preparing to fight an off screen foe, or being spunky with her upbeat childish nature? If I drew Captain America sitting down, I would probably draw him either mourning or tired from combat. I can't justify a good reason to have him sit. He's strong and a upfront as he carries a symbol as a hero. So I would only put him kneeling, or sitting low if something were depressing, agonizing, or in a matter of respect.
You should also take the next step and shade it (whether gradient or vector-esque comic book style) if it's going to a competition.
Don't feel bad, despite my review. It is actually better than what I can freehand (I'm a different genre of artists).