SharkESP did some work on Mystic Quest many years ago, but I can't find his site so I'm not sure where his notes are. I think he had an AOL site, but all searches turn up blank.

K, The following are what I have as the offsets for the weapons and armor stats.  For all of these, this is the first byte of the item's stats.  These don't  have anything to do with weapon graphics (I don't believe, at least).  (Sorry for the double post, wanted to keep this separate; I'd appreciate someone testing these out for me if anyone gets bored).  Hope someone can use this; geez, that took long enough o_O.

The honest reason is that many enemies in the game have access to petrification attacks way before you get the Aegis Shield.  There's this one battlefield after the Lava Dome which is mostly inhabited by Sthenos.  75% of the time you'll get an Unexpected Attack; I swear, I wasn't even able to put in a single command for five straight battles, because they'd petrify both of my characters before I even got a turn!  It just got annoying.

So, I wanted to hardcode petrification prevention into the Venus Shield as well, that way by the time I got to the Lava Dome I'd already be immune to petrify (I know you can do that with GG/PAR codes, but a hardcode just seems like a cleaner solution, and I like doing novice rewriting of ROMs ).  I've managed to do this successfully, too .

Also, I wanted to add some status attacks to weapons besides the claws (so now I've renamed Steel Sword "Ether Sword", lowered its Attack Power slightly, had it give a MAG +5 bonus like a claw, and it now causes Sleep when it hits successfully).  I haven't tried giving weapons new elemental attributes yet (for example, my bomb weapons cause Blindness; I'm thinking about trying to make them Fire-elemental, but haven't tested it yet).  I also have zero idea where the weapon graphics pointers are or how to manipulate them effectively (such as trying to give the hero the graphic for a Morning Star instead of a Battle Axe).

http://www.blitzkrieginnovations.net/mqme.html

I was working on this, but obviously life took away my excessive freetime.  I do plan on finishing it.  I really want to do a good quality MQ hack. 

If memory serves me correctly I believe the data for the items/characters are near the actual names.  I know at least one of them is...maybe monsters?  I can't remember as its been awhile since I messed with MQ.  What irritates me is for such a simple game it has a hideously compressed font.  As if they really were worried about having too large of a ROM right...they needed to save those precious bytes.