I made some very, very simple family trees to help keep some of the Norse gods straight. There's a lot more information to be added as the series progresses, but if I fill out the whole family tree now, it will definitely contain spoilers.
I'm going to add this semi-permanently to the "Extras" feature on the website. I'm also going to add some character descriptions. I also want to start working on a glossary of terms, but that's a lot like work, so... yeah, not a priority. But I think it will be a good thing to have in the long run, so I'll get around to a glossary eventually.