So basically these are all things we know as of chapter 1300 coupled with explanation
-The blacksmith legacy held a key to getting into the palace in the ancient domain. We saw LR next to the legacy
and either could have made a copy of the map or just watched ZX get the map and later planned to follow him.
-The ancient domain palace contained one of the 4 keys that are needed to get kongs greatest treasure Great
Codex of Spring and Autumn.
-Despite all evidence pointing to the key being in the ancient domain palace when ZX gets control of the palace he
cant find it presumably because LR has already taken it.
-shortly after we meet LR in the academy she talks about how she is looking for an object and no-one knows where to
find it. I made add a chapter reference to this if I have time.