How many Black Knights (Black Wings Generals) are there really?

Somewhat offopic: Has Alcaster been given any new storyline in the Mercedes or Demon Slayer quests? He was arguably the most important person of rebuilding Ossyria after Black Magician's defeat (built Magatia, made Orbis float, sealed Zakum, etc.), would be weird if they neglected him now. The Magatia storyline clearly hinted that he stole his alchemy powers from Black Magician's studies, wouldn't be surprised if he had secretly been an old follower of him or something.

That would be on-topic, since I can't rename this post. But it does hold relevance, since if Alcaster knew what Asmodius was doing and tried to stop him, it would've been easy for him to be remorseful for what happened during the Magatia incident. Alcaster also knows enough not to do what Asmodius did, and this is why he used many of the Black Mage's writings for good purposes instead of bad (Grendel most likely fell prey to naivete during his studies under Alcaster, since it's hinted that Alcaster trained Grendel.)

EDIT - Also note how El Nath is farther down the polar medium than Rien is; and remember that Rien is only snowy because of what Asmodius did to it. What if El Nath suffered a similar fallout effect after the Black Mage became what he did? That would also explain the inexplainable barren terrain in El Nath's deeper regions, and also why it becomes a volcano the further you go into the Dead Mines.