EDIT: The first person games released around the years after Ultima Underworld were more inspired by Doom and and Wolfenstein 3D, so I wouldnt rate the game as that influential. It took quite some time for anyone to pick up where it left with a more interactive first person gameworld...
I believe Might and Magic predate UU by several years, both as RPGs, and in FP view. The first MM was released back in 1986, and already had three games out by the time UU got out.
I'm only working from memory here, but as I recall, Ultima Underworld introduced the first-person perspective. I looked it up at Wikipedia and found this. Apparently, the folks who invented FPS credit Ultima Underground for inspiration.
'Shadowcaster' did have jumping, level sloping etc. It was from 1993 and preceded the Daggerfall predecessor Arena by a year.Wolfenstein, Doom et al didnt even have such a basic thing as jumping in them. Thats why I consider them different branches on the first person tree. IMHO Daggerfall was the first game outside the UU franchise to remotely pick up where UU left.
Ironically Shadows over Riva was the only one I liked, hehe.
2. Realms of Arkania I - Blade of Destiny
The Dark Eye was the first PnP-RPG I stumbled upon, and Blade of Destiny captured the feeling of the Game excellent... so much to do and to see
I remember enjoying this game a lot until I reached a certain point. There were bugs that kept me from completing it. SirTech (it was SirTech, right?) issued only one patch, leaving most of the issues unresolved. I remember calling SirTech, and they told me to buy the next game, because it would be a lot better.
Reviewers spotted the bugs and trashed it for that reason (maybe that's why it's a largely forgotten game). Too bad. It really was a lot of fun.
My German bargain bin version had missing files. I left the first clearing, and boom! CTD.I had the same problem back in the days with Wizardry VI - the german version had a game-stopping bug