Key? Right.
The Book Holder had once given Li Yelai a so‑called array map to open an Opportunity, which must be the key to unlock some legacy.
Each key corresponds to the legacy of a certain civilization.
With this many civilizational legacies, the "key" Li Yelai has doesn't necessarily belong to the Snake-men.
If he went through all that trouble to reach the Treasure Vault gate, only to find the key doesn't match and the door can't be opened, that'd really be enough to piss him off...
So... every faction that entered this Land of Opportunity probably has at least one key.
According to what the Little Mad King's avatar said, the Sea of Time wants the legacy of the giants. They probably have the key corresponding to the giants' legacy.
Sea of Time, Mirror Domain, Throat of Gui Xu, and the Ark Chosen Ones...
The "key" he obtained should originally have belonged to some faction, but because of the appearance and interference of a Variable, fate changed.
