The Secret of the Mithril Door

The Mithril door in the Whirlpool Dungeon has always been a perplexity among fellow adventurers such as myself. But today, I have discovered an ancient diary that tells us about the creation of the door, what's behind it, and how it got there. Please note that this is read exactly in the page. If something doesn't make sense, the page has either faded or is indecipherable. Here we go:

Chapter 1: Discoveries
 * Dear Log,
 * Today is the 34th of Rintra and I have stumbled upon the most magnificent thing: a dungeon underneath the whirlpool that I have stared at these many, many years! When I went down there, I discovered some amazing things: the new addition to the elemental fiends, the Waterfiend! And, the green dragon's ancestor, what I like to call, the Brutal green dragon because of it's tough scales and breath. For some reason, there was a pile of bones and so, I rummaged them, only to find a worthless pile of chewed bones. I was stuck for a while, trying to figure out how to leave, when suddenly, I saw a log raft! I was baffled at the fact that there is a raft in the middle of nowhere. So, I left and ended up at the end of the Baxtorian river. My old friend, Gerald, asked me if I was okay. I told him about everything I saw in that dungeon. He didn't believe me at first, but then I remembered about the chewed bones. I showed them to him and he was amazed! He was awestruck! Uh-oh, I have to go for now, Log.

~Ken Baxtor~