Although very late, here's my response to the tribal challenge. Incoming tl;dr alert!
The Skrii clan is a tribe located deep within the Amazonian jungle. To be precise, they are situated within the darkness of the jungle's valleys. Between the shadow of the valley and the thick canopy of tall trees' leaves, perpetual darkness shrouds the geographical emplacement of the clan. This somber blackness is home to fierce creatures such as jaguars and pythons, but also that of the being which is the very lifeline and essence of Skrii culture and survival.
Here, the Golden silk orb-weaver spider of the Nephilia genus strives. Its rich silk is of a primordial preciousness to the Skrii: with it, they are capable of constructing weapons, hunting, and building the foundations of their villages in a sedentary fashion. Mixed with the correct agents, the web can be made notoriously sticky and elastic, or hard. Nephilia spider web is well known to be an extremely durable material: it is no fiction that it can be crafted even into perfectly usable bulletproof vests.
In appearance, the Skrii are a dark-eyed, pale-skinned people. The latter can be explained by the lack of sun gradually diminishing the quantity of melanin in the tribes people's skin throughout the generations. It is not, as popular culture would have it, a result of all Skrii people being albino, which they are not. The dark eyes, though, are the result of a much less severe form of type 1 osteogenesis, present in the ancestors of the tribe and also passed on to every subsequent generation of Skrii people. Although the tribesmen lack the brittle bone-structure of the common osteogenetic individual, the trademark darkness of the sclera remains.
These features aside, the Skrii are generally very slender and of small stature, regardless of age and gender.
Skrii society is divided in castes.
As opposed to the majority of the other tribes residing in the Amazon, the hunter caste is composed solely of women, and for good reasons: for one, Skrii hunters are needed to be flexible in order to agilely climb the trees of the bottom-valley Amazon. These hunters, in the manner of the very spiders they so covet, are quick in descending from their trees upon sturdy webs and killing small game in a remarkable display of stealth and agility. This method of hunting terrestrial animals from above derives from the fact that the Skrii are almost completely incapable of camouflage due to the paleness of their skins.
The second reason is that the women, having more slender fingers in general, are more capable of working the web into finely woven traps. For similar reasons, weapon craftspeople of the Skrii are also majoritarily women. It is for this reason that Skrii have developed unusually long, flexible fingers.
Men of the tribe occupy spiritual roles as well as those of farming, culture, and education. One of the fundamental duties of the clan resides in that of harvesting Nephilia web. The "Weavers", a caste comprised solely of elder men less capable of performing the physical labors of farming, dedicate themselves to the culture of the perfect spiders' web: a particular practice that takes up-most dedication. These hosts accept to house broods of Nephilia spiders inside their own mouths during the major part of the day when they are not in the process of consuming food. In this way, the silk is kept perfectly humid, and the spiders are provided an ideal nest to reproduce in. This process as a whole is essential: given the fact that the Golden silk orb-weavers are very slow in casting their web, it is greatly important to breed as many of the spiders as possible.
Interaction with other humans is extremely scarce, though not unheard of. Given the remoteness of the clan's location, only seldom do passersby come across the Skrii villages. The Skrii are not reputed for being at all aggressive to these visitors, though hospitality is generally not shown to outsiders. They are more often than not left alone.
To the Brazilian people bordering the Amazons, the Skrii are referred to as "as pessoas gritavam na sombra do vale", literally "the shrieking people in the shadow of the valley" or, in short, as "as gritadores" - "the shriekers". This is in reference to the shrill vocal sounds that are commonly employed in Skrii language but are otherwise very uncommon in other cultures worldwide.
This was lots of fun. Ideally, I'd have liked to have done many more illustrations, but I didn't want to settle on this concept for too long before embarking onto something else. I'm quite satisfied with the pleasant layout, but what really made this exercise touch base for me was the concept. It was great to go and research all these existing animals, diseases, and such and such and incorporate them into a concept that (seemingly?) holds on its own two legs.
Challenge of the Week: Emotion +++
Questions? Criticism? I'll be sure to respond if there are any.