What a cute little guy . Instead of drawing him just sitting there you could give him action. he does look cute sitting there but give him live and character jumping, running, ect. Your colour profile picture is good but it would be better to see a front colour picture because your sketches show that his face has cheek hairs but you can hardly see reference of them in the coloured picture. You exclaimed he has a blue jewel but you should have a coloured picture of it. his expressions are great vary flexible depending upon the context of the picture.

Hm. I really like how Darius is portrayed here. A small little siyo kid with that sort of innocence and curiousity about him. His posture isn't so bad.

I like the joyed expression because it does in fact fit him. though the sorrow expression looks more like he's sighing in disappointment rather than looking down.

Although.. his hand as drawn here looks a teensy bit awkward. It's as if the bone itself is so thick, it rips out of his finger tips. Maybe it'd help if the claw tips were a bit smaller? Well at least the foot looks alright. It's the hand that needs a bit of work.

Hm, actually, the sitting pose ( the lower waist ) seems a tad off as well. May wanna work on that. It seems like the thigh, knee, and ankles are one big sausage with the foot sticking off it. Could just be me though

All and all I'd say this is a really good ref. You got everything down to tail spike. And the style you have going with it really works. Well done. Now let's see if other people actually use it.