There is no Epoch used in-universe in the world of Usiren as AD/CE or BC/BCE is in the real world - years are generally described by the regnal year of the monarch in whatever place the discussion is taking place in. (Sometimes years are given with both the local monarch's regnal year, and also that of another monarch, such as the King of Usiren.) However, for the sake of simplicity (and not having to correlate dates with multiple king lists), we will use the epoch of AM (anno mundi) representing the year since creation, ostensibly. (While there are obviously responses by superhuman beings to prayers and sacrifices in the Usiren universe, that does not imply that all of the cultural beliefs concerning them, much less the associated cosmology, are literally true, and so the choice of "AM" should not be taken to imply anything about the actual age of the universe beyond that it existed for all of the events on the list.)
The current year is 7802 AM.