The sketches are fantastic. It's so interesting seeing each character at three different ages, and seeing how you've conveyed the changes over time. The Kiri one was particularly interesting to me, for some reason.
You favor the meso-ectomorph body type, like most anime fans. Curious. If you want to expand your artistic sphere, I recommend studying other body types. Try a ecto-endomorph for a female; that can have good results. Or maybe a ecto-mesomorph for a male.