Heroes in Heroes of Might and Magic V: graphics, biographies, skills...

I'm not quite following – why is there a reference to the great and terrible Sandro in the biography of the Necromancer Lucretia? Is there a connection between the old world and the new one, or not? If not, then who is this look-alike, and if there is a connection, then why is so little said about it that I haven't heard anything?