Walleye

Walleye was... born? created?? animated???... within, which is to say 'of,' which is to say 'co-material to' the walls of an early Second Age temple of obscure purpose, caved-in and buried by a pattern of geological activity that ended long ago. Walleye can create an entity-body for itself to manifest in person within... itself, or rather its building-body, and can rearrange, remodel, and to an extent redecorate its building-body at will. It is vaguely aware of its entire contents at all times, but if it wishes to have true sensory knowledge of any part of its building-body it must either be present in its entity-body or manifest eyes within the surfaces of the space.

Walleye's creators programmed it to defend and maintain the temple, but its fundamental limitation is that it cannot expand its own building-body, or leave it; so, for a full age, it remained sealed in a tomb to a long-dead culture.

Then Vinuelle's clan, situated unknowingly not far above Walleye's living tomb, expanded their lair and breached the temple... which, incidentally, expanded the boundaries of Walleye's 'temple' as far as its enchantment is concerned, connecting the original structure almost to the outside world by a continuous channel of worked stone. After some tense and spooky standoffs, both Walleye and the dragons became fairly sure nobody meant any harm and began a tentative peace.

(Walleye might've tried to befriend them even if they were graverobbers and vandals. Nobody's touched its purpose-enchantment in some time, and it's been very, very lonely for a very, very long time.)

Having coexisted with Vinuelle's clan for some time now, Walleye has a limited command of the standard dragon tongue, Coatl, and... whatever Qumuel speaks, and Slixini is working on learning some of Walleye's native tongue. The clan is carving a worked-stone pathway to the mouth of the natural cave where they built their lair, with the hope that Walleye can see the outside soon.

Walleye now manifests its entity-body in the form of a guardian dragon because, well, it literally is a guardian!