Legends Z-A as I play

I noticed how they said 3000 years ago and AZ witnessing the Darkest Day

I could be wrong, but I think we might get some info on the Darkest Day in theDLC

I don't know how, but I'm a theorist, so I just say my hunches with limited supporting evidence and hope I'm right!I also think there might be something about Z-Moves

L mentioned them after I caught Zygarde and I never played S/M so I don't know when the Tapus were grabbed Z-Crystals, but if you know when could you tell me if it was around 3000 years and could somehow fall into this?

When the beam shot into space that might have been where Eternataus lives. It obviously got curious on where it came from and came to look, coming to Earth where it caused chaos. That sounds logical!