I have now searched every possible thing and the only other possibility I have come up with is Cronos. Except that there is the same problem with the Thoth theory, there is to much information about Chronos and Thoth.
I still gotta go with Nuada!
I am determined to find the identity of Marethyu!
These are the words I have searched alone and together.
King, injured king, hook, myth, mythology, ancient, one-handed, claws, hook hand, lost his left hand, left hand, god, mrtyu, marethyu, Ophir, India, Black eyes, Blue eyes, hooded, injured god, little known god, little known kings, nuada, tyr and a lot more.
Maybe this is all a trick and he has no identity.
The King of Nothing?
I think we need more hints to figure this one out!
Has anybody done better research than I have? What I've got is nil.