Alle Kunst ist der Freude gewidmet

Jugdral and Archanea are on the same planet, though the games set there take place about 1,000 years apart. Elibe isn't connected officially to them that I've ever seen, but some fans, including me, think Archanea is the world on the other side of Elibe's Dragons' Gate.

My take?

Elibe aka Ereb = Erebus = Hell. It's the world where the dragons were purged and banished, which makes it the "underworld" to the redeemed world of Archanea/Jugdral... which may possibly evolve into Magvel somewhere along the line but that's a different line of headcanon.

Which might be how "light magic" turned into "dark magic," maybe. But Roy kinda redeems Elibe itself in the end, by sparing Idoun.