I found the 5 notes, and so far I've got
I AM STILL TRAPPED INSIDE THE - I WISH - - - YOU MY KING - I NEED YOU
I think it's pretty obvious the first missing word is SEAL.
He's clearly not using punctuation, so it makes it hard to figure out what the rest of the words are. Here's what I got:
I AM STILL TRAPPED INSIDE THE SEAL. I WISH <pronoun/noun> <helper verb> <verb> YOU MY KING <conjunction> I NEED YOU
A few guesses
I WISH I COULD HELP YOU MY KING, BUT I NEED YOU
I WISH I COULD REACH YOU MY KING BECAUSE I NEED YOU
I don't think the remaining words could give any extra lore info. The only way it can give any information on the past is if it uses a contraction like "could've" or "would've," but that's inconsistent with the archaic voice implied by "I AM."