We had done a crossover with Level99 for their BattleCON: War of Indines Remastered kickstarter. They made two promo characters from us (Iskra Brimstone and Raederick Blackforge) and we made promos of two of their characters (Eligor Larington and Gerard Matranga). Whenever we print a promo we plan to eventually print that card in an official set, thus letting all of our fans enjoy it. We specifically picked Eligor and Gerard because we felt they fit the themes of PVS. I'm quite happy with how they turned out. Working with Brad at Level99 was a delight as well.
So, in short, this is certainly not a joke. This was an opportunity we had to help put our games in front of each others fans, because Level99 is a big fan of us and we're huge fans of theirs.