Pelagics: The fish-men have always worshiped the Heart, or whatever species/race it belongs to, in some form or another. The coming apocalypse is their sign to come upon dry land and conquer it from humanity, and they are having a ball. Some point in the journey you'll have to deal with the invading Pelagics by taking down a regiment of them that took over a seaside village they took over as a beachhead for the invasion.
Bloodsuckers: The mere existence of the Countess shows that vampires actually do exist in this world. While all the vampires fought in the first game were all despicable aristocrats turned into vampires who then birth clones of themselves as offspring, the second will be our first glance at what natural vampires in this world are actually like. As well as find if the Countess was merely a Large Runt......
Brigands: Sometimes, good old fashioned human cruelty, malice, and depravity can easily trump whatever horrors supernatural monsters can cook up. Like the ones from the first game, these guys will pop up everywhere, even among all the other monsters, taking advantage of the end of the world. Since the sequel will be a globe trotting adventure, there will most likely be multiple "tribes" of brigands, if you will, each based on a different Animal Motif in contrast with the Wolf motif the Vvulf and the higher tier brigands had going.
Cultists: Obvious. May even encompass members of the Church who fell into despair as the encroaching horrors became too much and their God is revealed to be the figment of their imagination they had conjured up.