They have 6 eyes and they’re ‘back finger’ is an opposable thumb. Some Kylaat’s have wings like this, which are more bat-like and have no feathers. Other Kylaat’s do have feathered wings, but the feathers are more like the birds on Earth that can’t fly and are ‘furry’ rather than traditional feathers.

Kylaat’s originally didn’t breathe oxygen, although it was present in Orn’s atmosphere. They have the ability to breathe pretty much any gas that’s most plentiful in an atmosphere. Now they’re on Earth they do breathe oxygen, but something about it gives them the inability to sleep so they constantly stay awake. This ability was used as a form of attack by Mestraal during the war on Orn, when he ordered the army under his command to start using what little oxygen was in the air to breathe, and they attacked the opposing army base while they slept.

Just by looking at them you would assume that Kylaat’s only have one mouth, but in fact they have three. The other two are located further back in their throat, and they can move and speak with all three independently. Because of the spell put on them when they came to Earth to make them appear like angels and have a more human anatomy, these extra mouths have been removed. This is why Hestron sometimes complains about the lack of depth in human languages, and often gets irritated when he has to ‘dumb down’ a Kylaat word so it makes sense and can be spoken by a human mouth and vocal range. Specifically when he introduces himself to new people, he makes a point of stating that his true name is much more complicated than just “Hestron”, but humans are unable to speak it. Because of how many sounds Kylaat’s can produce it was agreed very early on in their settling on Orn that they only speak one language, otherwise the amount of different languages that may have occurred over the course of time would have been immense. Despite this rule there are still variations in language when Kylaat’s speak in their original form, but none so vast that it could be thought of as separate languages.

Female Kylaat’s are physically unable to carry more than one child, even though sometimes they produce two embryos in the womb. This leads to the embryos trying to join in the womb and become just one. Sometimes the joining doesn’t line up perfectly though, and this causes birth defects like the one Parwine has. In his case all of his body is perfectly fine except his wings, which are partially deformed and stop him from flying properly. In bad cases the baby is so deformed that it dies very soon after birth, although it’s extremely rare for this to happen and a lot more common to have problems with just the wings.