So been thinking about Beast VI from Fate Prototype and a small theory is that L and R will be based on the two Beasts from the Book of Revelation (which we already known is ridden by the Whore of Babylon). Basically the first Beast is the one with Seven Heads and came from the sea (which could probably be the Primordial Sea/Tiamat in Fate). Meanwhile the second Beast "came out of the Earth" and is said to have "two horns like a lamb", and speaking "like a dragon". It also makes people worship the first Beast and is associated with the False Prophet.
The two Beasts aligned themselves with the dragon in opposition to God. I guess in this case, Beast VII would be the dragon. Than again we don't really know much about the Abrahamic God in Fate and Nasuverse (hell if there even is one considering everything). It could be possible that "Beast of Shame" mentioned by King Hassan could possibly be one of them, Beast V, or both. Caster of Limbo does refer to Beast VII as "Lord Satan" so there might be a connection there. There's also the fact that sometimes Satan and Lucifer are separate but connected beings, with Satan being one of God's angels who is a judge. So it may be possible that Beast VII has a L and R too? I would honestly say this more of an observation rather than a theory considering I'm sorta a newbie Fate fan. Not to mention the Ultimate Ones and Gaia/The World considering Type Mercury might show up in Lostbelt 2. Hell shouldn't the Ultimate Ones arrived in those worlds of the Lostbelts? Well, lets see where this goes than. You guys got any thoughts?