Can’t find an English source so linked to a Japanese one. Feel free to put it into whatever translation site you use.
Basically a Werewolf game with Frieren-favored illustration cards. Some samples can be seen in the linked tweets from the serie’s official account in the article.
Note: Fern’s card is called 「洗濯の魔法使い」, the clothes-washing magic user :-)
Interesting that Aura is on the cover art along with Frieren. I guess she would be the closest thing to an antagonist from the first season of the anime. I do find it interesting how popular Aura has become after the anime aired. It’s not like Aura wasn’t liked before, but I think episodes 9 and 10 of the anime took that whole sequence to a new level and cemented Aura (and her end) into a ton of people’s minds.
I imagine it’s also because the werewolves in this version of the game appear to be demons (which actually makes a lot of sense), so it also depicts the two sides in the game.