Kaga and Tirnanogue

If Tirnanogue/Tilnanogue were only the name of the place where Celice and Friends grew up, we wouldn't need to spend much time on it.  It's another mythological reference in a game packed with them.  But since Shozou Kaga went and founded a studio named Tirnanog after leaving Intelligent Systems, it would seem to have a degree of significance in the man's psyche.  But what is Tirnanogue, anyway?

( If you think these myths are nuts, you should see the versions that aren't cleaned up. )