Tomochika cocked her head. They were incredibly hard to describe. Among the animals Yogiri knew, the closest thing he could think of was a gibbon, but these had four arms. Two long arms were being used to grab onto and travel through the branches. The remaining two held primitive-looking black stone tools. They had legs, but they were short and thin, seemingly not used much for a life in the treetops. In all, they looked like some kind of monkey, but their skin was green and hard. Their faces were shaped like upside-down triangles, and they had enormous eyes similar to a praying mantis. They almost seemed like insects that looked like monkeys.

...

The first impression the elves gave was like that of a primitive, tribal people. Yogiri wasn’t so arrogant as to kill people like that just because they were in the way.

-Volume 7 pages 190 and 193