What realm would he have visited to see them?
I thought they all disappeared except for the one on Morrowind.
http://www.uesp.net/wiki/Morrowind:Yagrum_Bagarn
Thing is, the plural and the singular for Dwemer are the same word. So Fallion might be talking about the Dwemer race, a group of Dwemer or a single Dwemer.
Since we know for certain there was at least one Dwemer still alive at the time of Morrowind, and since he was under the protection of the powerful and ancient wizard Divath Fyr as well as infected with a disease that grants physical immortality, its not unreasonable to assume he is still alive.
Its quite possible Fallion is talking about him, it is also the explanation of what he says that makes the least assumptions about things unknown or unrevealed.
I have never heard this claim. Can you quote what he exactly says about meeting the dwemer?
When a vampire and talking with him about a cure he mentions having 'travelled the outer planes, and met Daedra and even Dwemer.'
I paraphrase, but thats the gist of it.
Thanks. This could always mean the Yagrum but we also know he is alive most likely because he was in the outer realm when the disappearance of Dwemer happen. That makes it possible there may be other Dwemer still alive in the outer realm. I wouldn't be surprised much if some Daedric Princes have had Dwemer as their champions in the past and are having those champions in their realms now. But this all is just speculation and I doubt if we ever get to know anything more about dwemer we already know.
Yagrum states that he has travelled a lot in his search for his kin, and hasn't found a trace of any of them. After that, he contracted corprus and finally found his way down in the corprusarium. He asked Fyr to tell him whenever he heard something about other dwemer.
Falion is probably referring to either Yagrum or something that he thinks is Dwemer, but is not.
Not sure if Yagrum would have been physically able to go a-realm-hopping again, to be honest, but perhaps he had company.