Not sure if intentional or an oversight, but the SDM website has been down for a while now.
Viewing post in SDM: Eternal Return Key - BAREGHOST EDITION comments
I have to change the URLs to point to wizardthieffighter.com - I shut down the SDM website because with the kids I don't have time to update multiple websites anymore. The rules reference is here: https://www.wizardthieffighter.com/erk-system-reference/