I don't remember the Time Reaper (which is a laughable excuse for a character) saying anything about Galamoth being from the future, only that he was sent by him.
As for 1999, petty much anything goes with that plot point since it hasn't been written AFAIK.
Actually here's some text to confirm:
Death & Aeon:
Death: Everything should be in place.
Aeon: It most certainly is. All thanks to your efforts.
Death: Now, what fiend would dare challenge my Lord Dracula?
Aeon: A messenger from ten thousand years in the future. Sent by one seeking your lord's throne of darkness.
Death: Then he must be stopped at once.
Aeon: Which leads to our final dilemma... The door will allow only a single being to enter.
Death: I see no dilemma. I will go -- through you, if need be...
Aeon: That is my desire.
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Dracula & Aeon:
Dracula: I've played your silly little game long enough. Time is secure now, is it not?
Aeon: Not quite. One last foe remains. A servant of he who hunts you from ten thousand years in the future.
Dracula: I fear no one requiring such absurd means to face me.
Aeon: With the final key the time barrier can be opened. Your final opponent awaits.
Dracula: Enough of your theatrics. Take me to him.
Aeon: Which leads to our final dilemma... The door will allow only a single being to enter.
Dracula: No matter. I will crush you and be on my way.
Aeon: You will not pass so easily.
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There ya go.
As for some insight on Aeon himself, here's his introduction:
As a guardian of time, Aeon journeyed through the ages.
One day, suddenly and without warning, a powerful entity appeared from 10,000 years in the future, determined to destroy the very fabric of time.
Aeon enlisted the power of thirteen mighty souls, setting each on a path that would lead to this great enemy.
With only a single chance at victory, Aeon must determine the most worthy champion for the battle ahead...
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And here's his ending:
Thus the rift in time was mended, and all were returned to their respective eras.
Of course, Aeon had no era of his own to return to.
Even now, he wanders time eternal, observing all that occurs. It is the only way to satisfy his infinite curiosity.
Whenever the fabric of time is disturbed, he -- or rather, someone he enlists -- will arrive to repair it.
And Aeon's role will remain forever shrouded in mystery...
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