Оö-Ëtavú

The Оö-Ëtavú refers to the upper skeleton of the Ibrófeneð, comprising the Ýyr-Оö and the Оö-Vanýst. In these dual roles it serves as the central line of defense for the brain and other internal organs, a structural anchor for the outer skin, that is, the Ýyr-Yožikut and Ýyr-Üpal, the Matošu, and the ears and eyes, and the main mode of transport for nutrients and other molecules. The Оö-Ëtavú comprises the second-largest continuous body organ, aside from the brain itself; it typically measures 30-35% of the creature's total volume, and 55-60% of its total mass.

Anatomy

The Оö-Ëtavú is split into two parts:

• The Ýyr-Оö comprises a roughly hemispherical canopy under which rests the brain.
• The Оö-Vanýst is a thin layer of specially-modified bone that lines the inside of the Vanýst, or digestive tract.

These two parts will be further elaborated in the coming sections.

Ýyr-Оö

Main Article: Ýyr-Оö

The Ýyr-Оö makes up around 80-90% of the total mass of the Оö-Ëtavú. It is in the shape of a roughly squashed sphere, whose thickness increases from 1-2 mm at the lower ends to a maximum of 2-3 cm as one moves towards the top of the sphere (near where the Matošu is). The Ýyr-Оö possesses a circular hole at the top, around 3-5 cm in radius, to which is attached the Matošu and through which an unobstructed passage into the creature's digestive system can be obtained.

As one moves down the sides of the Ýyr-Оö, small pinprick holes will start to appear; these, connected to transport veins from various sources like the Tewaðup and the Maprëhu, reach through the Ýyr-Оö and into the outer layers of skin, where they form the Üpal, the black scales that don the outside of the Ibrófeneð. At each ear, the Ýyr-Оö has a specially-built hole for them, providing the main structural lock for them and their nerves.

At the Vmýül, or the eyes, the Ýyr-Оö will diverge to make room for them, splitting into 8 separate spear-shaped extremities that gradually taper down in both thickness and size as they reach downwards.

Оö-Vanýst

Main Article: Оö-Vanýst

The Оö-Vanýst is an extremely thin cylindrical skin of bone that serves as the innermost layer of the Vanýst. Measuring around 0,5 to 1 mm thick, the Оö-Vanýst is made of a special type of bone that fractures into harmless shards when disturbed by a large amount of pressure and/or shock, which regularly occurs when eating or doing strenuous activities. This is due to the Оö-Vanýst being actually connected, via flexible filaments, to the teeth themselves, such that, in the act of biting and retracting, vibrations generated are dissipated through the Оö-Vanýst instead of traveling back beyond the teeth into the brain. In addition, the exposed portion of the material, especially around the fracture lines, is designed to dissolve easily when in contact with air, preventing clogging and/or buildup within and around the Vanýst and Tewaðup.

Thus, the Оö-Vanýst serves as the main force preventing trauma to the brain. All sets of teeth have nutrient channels serving the Оö-Vanýst, and as such, a typical Ibrófeneð can regenerate the Оö-Vanýst fully within 3-4 weeks, or around 1 month, given a healthy diet. However, in this time period, the Ibrófeneð must take care when eating, as any strong movement has a high potential of damaging the brain.

Symbolism

The Оö-Ëtavú's main role as a protective shell for the brain grants it special relevance in larger protector roles. It is often paired with the brain itself, or, to a lesser extent, with the Оö-Ŋüžtú, both of which symbolize the engine and the center of operations, in contrast with the guardianship role of the Оö-Ëtavú.