Why does the evil Tiga have no name, but Gedi has a name?

Because the evil Tiga was created by humans, even though it is a stone statue, it has changed into a stone statue in the ruins. Ultraman was just born and no one has given him a name yet. Gaidi existed in ancient times, so he has a name,,,,,,,,,,,, and the evil emperor looks like Diga "not at all", so he is called Evil Diga