DISCLAIMER: Your Steps and Tasks may be different
Below is the begining information for the Artifact Atlantis Tablet, if you know more information please send it in.
The Sphinx Callie mentions the Atlantis Tablet may be found at the Atlantis Library ("The Library" underwater. aprox loc= 40k 60k in Messo.) that is close to Treasure Island. You will need to slay the guard there for the Atlantis Tablet.
Guardian of Atlantis drops the Tablet of Atlantis.
Atlantis Tablet 1 of 3 -- dropped from a Naxos tetrarch and Naxos traveller Meso
Atlantis Tablet 2 of 3 -- drops from Sobekite Khu Rager, Naxos frostblade and Naxos rymester in Meso
Atlantis Tablet 3 of 3 -- drops from Naxos menders and Naxos umbral conjurer in Meso
Dialog from combining the 3 scrolls:
Can be used by all.
(Earns exp: Slaying enemies belonging to the Sobekite Khu or Sobekite Khem factions.)
Artifact also levels from RvR and mobs in Shrouded Isles Dungeons, as per patch 1.71.