I think, all your characters are looking like brothers and sisters. Especially on this sketch here. Your art is awesome, for that age you are supertalented, i love your way of using coloures and the whole style, but I can't help but realizing, that you perfect just one kind of face. i guess, that is something you can work on. Anyway, I love your art.
It's all fantastic, of course. I love your style, it's very manga, but has the realistic feel to it. The whole fantasy-come-alive feel of the manga style is also very strongly present in your themes, which are always original and creative. Something that made me laugh was that bottom left looked like Draco, and bottom right looked like Harry. From Harry Potter. Anyways, brilliant. It kills the aspiring artist in me that these are your sketches.
These are all amazing. The one on the top right reminds me of zell from Final Fantasy VIII. But Zell's tattoo was on the opposite side of his face. ^^' The painting that I like the most is the woman on the top row. I love her soft look and how you left parts of her hair as brush strokes.
Top right is my favorite since his eyes are really piercing out of the overall sketchy drawing. But all of your characters in the painting are looking kinda melancholic/sad. A reason? My imagination? We'll never know..