I’ve always liked ioun stones, one of the more iconic magical treasures in Dungeons & Dragons. I mean, how can you not? They’re these floating gemstones that orbit around someone’s head and grant them abilities and powers. I always wanted to have one in a game, but never got the chance, so instead, I went and wrote a whole sourcebook about ioun stones. I took the concept as found in D&D and in the original Jack Vance story from where they came from, and expanded the lore into a whole exercise in world-building, which was both a lot of work but also a lot of fun.
Inside the book, you’ll find rules for making your own ioun stones by rolling on (or choosing from) a series of tables, as well as information on other forms of ioun crystals. There are some NPCs that can help tie all the new info into your own campaign, ancient lore if you’d like to give your ioun creations some backstory, and creatures to fight against or seek alliances with.
The book hasn’t done as well in sales as I hoped it would, though, which given it’s iconic D&D-ish topic, has me a bit baffled. I opted for a rules-light approach, using generic stats and rules that could apply to any D&D-adjacent game or be easily adapted to other systems in order to increase reach, but sometimes I wonder if that hurt the book instead. I stand by my decision, though, but I still wonder. Ultimately, I think the book just needs greater promotion in more D&D-focused channels, and for fans of the book to tell others about it.
So take a look at The Ioun Codex (print)(PDF) if you haven’t yet, I think you’re gonna like it. There’s also an Appendix if you’d like to get even more ioun content. And if you’d like to help me out even more, tell others about the book as well.