I believe it is from Poseidon it makes the most logical sense considering it probably wasn't P/Pedro's Grandfather. The Letter (to me at least) felt like a father apologizing for failing his child when they needed him.
omg yeah i feel the same way. I'm hoping i find his vote soon. It gives this impression of a creator morning over their work yet unfinished. I really do hope to see what the other gods have been holding up.
I think that Athena imprisoned our boi so that they would have an immortal believer so they would never disappear making the Greek pantheon effectively immortal.