Who was sypher dias in Star Wars?

Sifa Dias was a Jedi Master that was on the Council around the time of Episode 1. My speculation is that he becomes a member of the council after the events of The Phantom Menace. Then he is killed before the events of Attack of the Clones. I think that Dooku may have called himself "Dias" when he told the Kaminoans to build the clone army. He then hired Jango Fett to be the DNA template for the clones under his true Sith name Darth Tyrannus. This detail is never mentioned in the movie but if someone spends enough time thinking about it as I have, it's obvious. Sorry about the long answer but I get cared away on these things.