Despite all their flaws, LoI and Cod on PS2 featured a number of interesting ideas, that ended being kind of cliffhangers.
Ebenite and Crimson Stones were never heard about again. Neither were the whereabouts of StGermain and who he exactly was, kind of agent of Good?
Were those episodes on PS2 so unpopular Konami decided to get rid about those ideas?
Alchemy was rampant particularly in the 11th Century, the more centuries passed the less it was heard of with the globalisation of chemistry.
LOI speaks of 4 stones of Alchemy and only ever mention 2. (My theory is the other stones where something like Emerald and Ivory, which together with crimson and ebony, could have signified the 4 cardinal points.*)
*It is also rumoured that emeralds may have age reducing properties, though I can't verify this myself

ST Germain is the historical figure/ Master Alchemist who achieved the true goal of Alchemy (as per LOI's story) which is eternal life. He can observe things and is not limited to time and space, though he does mention during COD after his fight with Hector that the Masters/ higher forces won't let him interfere with history - so the battle ends. During the battle he uses techniques such as "Time reverse" and "time advance"
My understanding was that St Germain is the opposite to Death, in the context of LOI. Zedd seems to be more trustworthy than him but later on we find out this is not the case. He is also fought at the clocktower which juxtaposes the general association of fighting Death.
Didn't IGA already confirm that Mathias/Dracula used the stone through the centuries to become stronger?
I'm pretty sure it was in a interview he released around the time of Dawn of Sorrow.
Crisis posted the same interview in the LOS topic not to long ago.
I believe the point of Dracula having the Crimson Stone (which is sometimes shoehorned into artwork as a neckpiece or broach etc) is that when he dies, he absorbs his own soul (since the stone allows the user to absorb the soul of vampires) This explains why Dracula keeps returning and provides both physical and metaphysical logic as to why.
Hence, when he resurrects he comes back with the previous power he's accumulated and then some. This would potentially mean that when Julius completely destroyed him in 1999, he was at his absolute most powerful.
*EDIT: Also I assumed when Mathias abosrobed the Soul of Walter that he too absorbed the
Ebony Stone, which would explain why the Castle keep can be kept in eternal night for Dracula's resurrection..