About the name change from Occult Mod to Underlord; Occult was one of many working titles I had--one I chose when I realized that I was taking the rogue mastery in a direction just far enough outside of Rogue that the mastery couldn't remain with that name. Since this was the core of the mod, the Occult mod seemed a more fitting title than "Shadow Rogue." However, soon after I began working on the other masteries. I didn't change the name then, because I'd already changed it twice. So, instead of worrying about it, I simply made a personal mandate to stop changing the damn name, and just make the mod and let it be what it was regardless. However, once it became clear what the mod was, and with the end in sight, I knew it was time to find a better name.
Zilla, Yerkyerk, and Jiaco all weighed in with great name suggestions. Truly great name suggestions with names that sounded much cooler as well. However, Underlord just clicked. And, once in place, I knew there was no way I could change it to anything else. Since this project is so much restoration--finishing what the developers started--it was a nice way to rename the game itself as well, allowing the title to reflect the existing plot, and playfully on a number of other levels that players new to Titan Quest won't get. :)