To be more precise, that ancient hero, Genos(as in Genos Island, the island at the end of the game), an ancestor of Chester & Elena Stoddart, who originally sealed Galbalan(Demanicus). But he settled in the area, & IIRC, started up the town of Redmont(Kenai). At the end of the game, when Chester goes down to seal away Galbalan again & destroy the island, it's because he & Elena are only capable of it, being descendants of the original hero. I don't think it's ever been explained how that Galbalan got over to this particular area. It must've been some human(probably an ancester of Ernst & Geis) that used Eldeenian technology to try to create white &/or black emelas, which is how Galbalan's end up existing. They are made up of ash emelas(emal stones) which is a by product of a human trying to make white or black emelas. Only Eldeenian's can create white or black emelas.
The wiki on the series is quite accurate from what I can tell by scanning thru it:
http://en.wikipedia.org/wiki/Ys_%28series%29I think in Ys 3, it seems like he's talking about Adol, but, I've gone over the cinema a million times, & I do think they were not trying to say that Genos was Adol, but, I could be wrong, I haven't talked to the janiter that did the opening cinema, to see if he knows if he was talking about Adol, or a different person alltogether