As with the other recent posts, I am moved to steal ideas from animated movies.
The Secret of NIMH includes the Great Owl, a terrifying source of knowledge and wisdom to those who are willing to brave his home and attention (as Mrs. Brisby notes, "Owls eat mice"). The cool thing about the Great Owl is that the inside of his home (an exceptionally large hollow tree trunk) is rife with age and neglect. It does not resemble a home so much as a violate tomb, as cobwebs hang from every surface and bones lie strewn across the ground. The Great Owl himself is covered with cobwebs as though he has stood unmoved for years (though he leaves after speaking with Mrs. Brisby and the impression is that he leaves every night to hunt). Pests share the Great Owl's home as evinced by a large moth accosting Mrs. Brisby as she slowly makes her way to the audience chamber and a very large spider (she could fit beneath is legs) stalking her from the shadows before the Great Owl crushes it with a talon.
Plenty of ideas there. Since Trokair thrives on personifications of abstract ideals, Knowledge could very well be an unmoving, contemplative, giant owl entombed within a supernatural/fantastic library containing the sum total of wisdom throughout all time. Gaining an audience with Knowledge would be an epic task indeed.