From a movie based on System Shock to a reference to the Crusader's WEC in Earth's history, Wing Commander has aways been happy to nod at Origin's other great franchises. The Ultima series, on the other hand, went even further--with several elaborate tributes to Wing Commander... and Ultima Underworld was no exception!
Ultima Underworld II introduces the "Trilkhai" (an anagram for Kilrathi), a race of telepathic cheetahs, to the Ultima world. While visiting Killorn Keep you may discover any number of these creatures wandering the castle. Clicking on any of them asks you to visit the stables for more information. When you do you can meet their leader, Blackie, who explains that his people are now slaves but that they once flew among the stars! This even starts a minor quest where you are asked to find more information about Trilkhai history.
Blackie: ...(Player Name)? I... see... in your mind that you can be trusted. That you are not from this world. That you are an... Avatar.
Avatar: Yes, that is correct.
Blackie: We have need of a... helper. But I see thou dost know nothing of our situation. The humans named us "Trilkhai." They do not know that we able to communicate in this way.
Avatar: Why don't you tell them?
Blackie: They might become afraid of us, and destroy us. It is safer that they think of us as animals.
Avatar: Then why entrust thy secret to me?
Blackie: I see that thou hast virtues that will prevent thee from betraying us. We must risk this, as many of us have need of a human agent in the keep.
Avatar: I will help thee where I can.
Blackie: Human, I am the oldest, and I have heard many stories of our race's past, wild tales of Trilkhai who flew among the stars, and hurled fire at the humans. I would learn if thou hast met any being who has knowledge of this.
Avatar: I have heard of none, but I shall look.
Blackie: If thou couldst learn the truth, it would be of great service to our race!
Towards the end of the game, while exploring the Ethereal Void, you encounter 'Wisp'. Trading information gives you the history of the Trilkhai and concludes Blackie's quest: "Trilkhai were once a powerful group of anhropomorphic 'felines.' Since their catstrophic 'loss' to a group of humanoids, they have since devolved 'past' the point of 'tool-using'." Guess Tolwyn was wrong! (Or was he? Origin's guide to Ultima Underworld II explains that The Guardian is breeding Trilkhai for an uncertain purpose...)
If you're trying to make sense of the whole situation, you probably can't--it even directly contradicts Ultima VII's Wing Commander reference, which has a Bloodfang with a live 'Kill Wrathy' discovered in a farmer's field a year earlier (having crashed within living memory). The Trilkhai telepathy is also sort of funny, as it's the only trait the Kilrathi hadn't already borrowed from Larry Niven's Kzin!