I have read so much backstory to answer this.
Two conclusions. One: so this is where that Changeling the Lost thing from a previous ask came from!
Two: it makes sense that I have never investigated this franchise before, because I do not like horror. And this is... very much that.
Therefore. The Chain, being very confused, and also having learned more than one lesson in the past about immediately trusting the people who say they're your allies (looking at you, Byrne), immediately take about five figurative steps back from the situation and start analyzing.
One week of analysis later, their conclusions are as follows.
-Ganondorf is claiming to be a second-generation vampire, whatever that means, but it does seem to get him a lot of authority in his own vampiric sphere. All his turned vampiric followers are female, which could mean several uncomfortable things that the Links are not going to think very hard about. On the other hand, all of his victims are... indiscriminate. To put it nicely.
-He seems to think that vampires ought to rule the world. He also seems to think that he himself is a fantastic candidate for World-Ruler. He also doesn't seem to think that revealing the existence of vampires in order to subjugate said world is all that big a deal.
-This is causing problems with Mido, who aside from everything else is quite set on all creatures remaining unseen and unknown. On first glance, this seems like a better option than Ganondorf.
-On second glance, Mido is willing to murder any number of bystanders, human or otherwise, in order to keep this secret. He is maybe... not a better option than Ganondorf.
-Meanwhile, the local Link is running a faction dedicated to protecting the humans and innocent bystanders, which finally seem like the one good option in this place.
-...But on second glance, he's also willing to murder any number of creatures, vampiric or lycanthropic or otherwise. Which is, again, not really a better option. Surely somebody in this place is at least a little bit opposed to murder?
-Oh wait. It's the Chain. The Chain is opposed to murder.
-Time to create a fourth faction they guess.