Deity has been in development for years but is finally in a state that I think works very well and with significant content that makes it appealing (and usable) by gamemasters running campaigns on Hârn.
There is a tutorial of Deity’s basic featured offered upon first loading the app but it’s useful to make that experience available to a wider audience. As of today, a walk through of the tutorial is available on YouTube along with a commentary of what is going on.
To try Deity yourself, go to https://deity-online.com/. It’s completely free to use!