Originally Posted by
Huralok
Working with the Gaulish Mercury or Esus connections most likely. There could be other things at play here, though. Like Cu being a descendant of the One-eyed Irish Allfather, the Dagda, through both his mother and his mortal or fairy father (not Lugh, but Fergus’s brother whose name escapes me). Or how Setanta, a name with interesting meanings, doesn’t appear to be an Irish name, and seems to have connections to the Gaulish Mercury, among other figures. It all depends on the research that TM has done into this rather large topic.
Since we’re talking about the Gaulish one, this may also be worth mentioning: I believe there are records where Wotan is referred to as Mercury.
Personally, I wouldn’t be surprised if Nasu used the reincarnation elements in Cu’s actual mythos (eg his older birth story) to tie all these things together.