You found something quite strange, for sure. By your description, I agree that it surely some product of the Undead. Considering we had an actual Lich just over the bridge, I am not at all surprised.
Perhaps with your help, we can cleanse this putrid shrine and, in doing so, help Johan regain his farm. I will need six Blazebug Embers, though. They are not overly common, but you can find them just east of town.
Welcome back. You have done very well and now we may proceed.