Hi Barkeep - I love the attitude and imagination in your work - are these your own original characters?
I hope you don't mind but I took the liberty of doing a paint-over for you on your demon character - please bear in mind that I am still on a journey like you so please feel free to ignore if this doesn't work for you.
According to Andrew Loomis, for idealistic proportions, the level of the nipples should fall midway between the top of the head and the crotch:
I noticed that your character didn't quite match this so I did the following:
1. Lowered the bottom of his pectorals.
2. Elongated his neck a bit.
3. Beefed up his arms a bit (this is just a personal preference thing and doesn't relate to the proportions of his torso).
Hope this helps - please ignore if not - but either way - keep going :).