Amazing work. I have found it while searcihng for a picture of creature called Forkul Asail from Steven Erikson novels. Then I saw your other pictures and now you have at least one more follower. Amazing work and concepts for creatures.
Throughout the storyline of the books, the slivers were noted to have evolved to mimic the abilities of the creatures with which they coexisted. I suppose that they began to take on humanoid form after a while.