According to Wikipedia, the Emperor fought him in the first millennium, hence not the bronze age. (Unless the person who added that forgot to add a "BC", in which case you're right.)Undead Dragon King said:That is one of the C'tan gods of the Necrons called the Void Dragon, and he is special in that he can control machines. He is currently imprisoned in a labyrinth deep below the surface of Mars, placed there by the Emperor around the time of the Bronze Age.
My favourite has to be the T'au. I mean, they developed from stone-age hunter-gatherers to a major (if small) high-tech space-faring empire in six thousand years, and given time, who knows what new heights T'au technology will reach.