I guess this is another relatively simple one, but I'm happy with the composition and linework so I'm not going to add any more. Achaierai have actually featured on this blog before in another creature's entry, but I really don't like the drawing in question so I'm not going to link it! Ha! The way I've drawn it sort of hunched over reminds me a little of a xenomorph, or the delightfully-named "deacon" creature in Prometheus.
The description doesn't mention a tail, but I felt that adding one gave it more of a catlike feel. The head is modeled off a recoloured Zebra Finch, which I think is a fine-looking bird. I didn't go crazy detailing the feathers because it feels a bit more smooth and alien this way. Like, this creature is not a bird, it's something much worse that happens to look like one.
PS - Bosch, anyone? the guy was definitely fond of torturous man-birds.