I've been working on a new system because I wanted full control over being able to make digital apps and games around it. If you use an existing system, you're having to adhere to a restrictive license telling you what you can & can't do, how to credit the existing work when you are allowed to use it, and it's just a huge headache. Also, most of the existing tabletop RPG systems I've played don't match a video game setting very well. I am new to building a tabletop rpg system from scratch, but I'm trying to come up with something that can be played with pen & paper or as a digital game.