So, while writting my Castlevania Split Timeline hypothesis and figuring out what game would branch from what event, I realized that Cornell is not the only one in Judgment to come from an alternate timeline: Death and Carmilla also are, and they come from the same one as his.
This is simple enough to explain: Death and Carmilla know Cornell from his "Blue Crescent Moon" moniker, and nor Cornell or his moniker are a thing in IGA's timeline.
One could argue Death is omniscient, but this is simply not true, as
I have demonstrated here.Carmilla has no excuse: Either she came from Cornell's timeline, or there is no way for her to know who he is.
Finally, one could say that Cornell exists in IGA's timeline, but is simply not mentioned, and that's how Death and Carmilla know him. This could be true, however Cornell, while talking to Death, says this:
"Ask as often as you will... but I will never serve Dracula."This implies that Death has tried to recruit Cornell before, and we have notice of NO SUCH THING in IGA's timeline. Again, this could be shalked up to "offscreen recruitment" but, more importantly, I raise you what Death says if he defeats Cornell:
"With this, the Master's next reincarnation is assured."Where do we see Death try this scheme? Yes, in LoD. He takes Cornell's wolf soul and uses it to ensure Dracula's revival. The most important part here, however, is not the plan itself, but where it comes from: In LoD, Death reveals that this scheme was DRACULA's idea, not his. Therefore, him using Cornell's soul to "assure Master's next reincarnation" is a command issued by LoD-timeline Dracula. Also, notice how he says "reincarnation" and not "revival" or "resurrection" -- he's talking about Malus.
Now, the next logical question would be "But Death knows Alucard from IGA's timeline!". Indeed he does -- this is why I'm working on a split timeline. I believe Judgment's Death comes from Cornell's timeline AFTER it split from a point in the main timeline. This means that Alucard indeed exist in LoD's timeline, and whatever was the reason for the split, it was after SotN.
While I can't point Carmilla, I'd say Death comes from just before LoD,
or even from the time between LoD and CV64.
EDIT: No. He certainly comes from before LoD's ending, but after Dracula planned to use his soul to reincarnate. He already knows Cornell, yet he doesn't possess his soul yet, as evidenced by the line he speaks in Judgment that I posted above. If he came from after this, Dracula's reincarnation would already be assured, no matter if time-rift Cornell dies or not.