The Summoning Circle in Magus's Castle

[V_Translanka]

Maybe it's simpler than that and instead of representing four directions or horsemen (or w/e), it's simply split into four to represent the four Magical Elements.

[curufeanor]

This does seem like it may be something meaningful. There are a Zodiac wheel and a summoning circle in Final Fantasy Tactics and people took years to realize there was a lot of symbols hidden in there (with even names inscribed in a made-up alphabet). Maybe this CT circle has some meaning too.

I don't know enough about Hindu/Tantric/Buddhist symbolism to make up some theory, but I think this circle looks a bit like a Mandala. Since Magus' Japanese name is Maou and Maou is a Buddhist concept, maybe there's a thematical relation.

Fortunately, Magus's name in the Japanese is spelled in kanji (he's the only character with a kanji name, and one consequence is that if you change his name, you can never change it back, since the name selection only has kana).  Since it's spelled in kanji, there's no need to speculate about what it means.  It is 魔王 and means "witch king" or "magic king", whichever you prefer.

In fact, the idea of "Magus" being his _NAME_, seems to be a translation invention.  In the Japanese, it's more like they're just calling him "the witch king" (Japanese doesn't have articles like "the").

[Chrono'99]

That doesn't change what I said at all

[curufeanor]

That doesn't change what I said at all

I wasn't trying to change what you said, just pointing out there's no need to speculate.  I'm not knowledgeable enough to know whether there are Buddhist connections for that word, that'd be an interesting question to find out, kind of like asking whether "devil" has roots in Christianity even though nowdays the word can be used much more broadly.