A is for Arpex.
Arpex visits us from the novels Trust and Chain of Gray. For a long time, Arpex was simply known as "the blue creature". After he was upgraded from the creepy creature that threatens the MC in a single scene to a full out Council Member hidden under robes that threatens to eat the MC and does eat his ex-girlfriend and then goes on to play a big role in the sequel, the creature got his own name. Or name for his alien self, really. All Arpex share the same name.
Arpex is described as a tall, blue-shelled biped with small frontal appendages ending in claws. It's feet are sharp, being covered with the same (unfortunately...depending on which side your on) bullet-proof covering as the rest of it. It has no visiable head and speaks the common language only through a speaker box attached to its upper body. It prefers its own language of clicks and hisses, but few seem to understand his threats this way. It has large wings, or jaws depending on if it's eating or flying, that spring from its back which are used to engulf its prey. These wings are edged in sharp talons and secrete a disgusting ooze of digestive acids. Or hey, maybe they're really appealing acids if you happen to also be Arpex.
Likes: Eating soft-skinned things, unflattering bright yellow light, the idea of turning the MC's homeworld into nesting grounds.
Dislikes: A messy plate, slaves that forget their place, brain-dead food.