According to an article by ThisIsGame (a reputable South Korean videogame news site), ArcheAge does in fact use CryENGINE 3. We had speculated on the meaning of XLGames’ appearance in one of Crytek’s CryENGINE 3 promotional videos a few weeks ago. Now we know for sure that our favorite MMO does, in fact, make use of parts of the updated engine.
"Kakao Games and XLGAMES are today very happy and thrilled to announce the arrival of ArcheAge’s Summer Update, which is available for players to enjoy now." - Kakao Games and XLGAMES.

"It is with great excitement that Kakao Games and XLGames announce ArcheAge’s first content update of 2023. The Spring Update will include a wealth of improvements and reworking of in-game features, engineered by the development team to continue enhancing player experience." - Kakao Games and XLGames.
"Following the positive response to ArcheAge: Unchained’s previous Fresh Start Server, Kakao Games and XLGAMES are delighted to announce the launch of an all-new Fresh Start Server for the beloved MMO title.
The new server will be accessible to ArcheAge: Unchained players on February 9 and will include a host of new improvements to server specifications based on user feedback." - Kakao Games and XLGAMES.
MMO with CryENGINE 3, that sounds impossible and but if you think about, it can be really cool to have RL "feeling" and shading.
This should serve as a Very slight hint at what Kingdoms may looks like. Kindgdoms will undoubtedly look better but its still a hint.
Me love PC!!
Aion is also CryEngine i believe.