Strangers' Document

Even though I keep my ears open, I was late in receiving this information. I heard the Genius and you are looking for the Hundred Swords, is that true?
Every Blacksmith wants to touch the one of a Hundred Swords Zian had. So I am also collecting information. Let me give you a piece of advice.
I will tell you a story about a person who was searching for the Hundred Swords. A man was eaten by a monster on the plains and I heard a group talking about the incident. A Marylith Lady Lilith at Summer Beach swallowed the adventurer along with the letter you've been looking for. Try to find it!

Although this may have nothing to do with the Hundred Swords... I heard the<HFFFA7272> Marylith Lady Lilith<HFFFFFFFF> at <HFFFA7272>Summer Beach<HFFFFFFFF> had swallowed an adventurer searching for the Sword along with the letter you're searching for! Try to find that <HFFFA7272>letter<HFFFFFFFF>!

What? The letter from your master? Why was the letter inside the stomach of Lilith? I don't even understand why the adventurer had it with him in the first place. I think it's safe to say he tried to take it with him.
By the way, why is Mathematician Genius the intended recipient and not you? Haha.