Wow! So Kairos is from Karonte maybe?
I feel like that would be a bit of a stretch as Kairos doesn't resemble anything like Kharon/Charon, and his theme/character doesn't seemingly resemble Charon's myth either. Kairos itself is apparently the Greek word for time - they had both Chronos (name of the father of the twelve gods) and Kairos. Kairos signified more as "Good time to take action", probably to describe something along the lines of "it's time to do this/would be a good time to do this". This aligns more to the Kairos we saw in the first timeline as he clearly worked pretty meticulously to be able to stage a rebellion and take the crown from Raymond but that's really about it. Charon in greek mythology is a guide for the dead but Kairos is just a psycho murderer with an obsession.
And actually looking at it again there IS actually a god named Kairos, who had the same "meaning" as the word. He was the god of opportunity. This guy is probably Kairos' patron or something lol with how he managed to take the throne in the first timeline.
Wow thank you for this information
Thank you ヾ(☆▽☆)
BTW for anyone who doesn't know Greek mythology, Lethe is the name of one of the rivers in the Underworld, it wipes memories just like Lethe says she is oblivion :) I assume her presence alone is a similar thing which is why everyone will forget her once she leaves