I realised within about two and a half minutes of starting up Arx Fatalis that it is a UWAW game. Unplayable Without A Walkthrough. I find that’s the case with most games that came out before about 2004, and Arx Fatalis was released back in 2002. Newer games often just come with a two-page insert with a diagram reminding you where the controls are: the rest of the game is instinctive. You just pop the disc in and go.
Arx Fatalis does have a tutorial, but it’s tricky to get used to. For a start, you can toggle between mouse-look and directional arrows, but in order to interact with anything you have to flip back to the directional mode (and this isn’t actually explained). Beyond that, it falls somewhere in the middle between being entirely intuitive and outright fiddly. About half of what it does works the way you expect it to, which isn’t too surprising given its age.
It looks like Thief, though it’s a first-person RPG released the same year as Morrowind. The Looking Glass connection is explained in Arkane’s assertion that they intended Arx Fatalis to be Ultima Underworld III, but couldn’t get the licence.