Are the dungeon's meant to be "cleared" in linear order? I tried to get inside the mountain castle, but it was locked, so I kind of assume that's the case. If so, is the order Cave>Castle>Temple?
I'm probably not the best person for information in regards to dungeons, but I thought there was a mine dungeon as well? I'm not so sure now, cause the NPCs like to make things up sometimes.
I do believe you can finded key pieces in dungeons and once it's whole you can enter next dungeon.
I think the "cave" in the north-east counts as the mine. As far as I'm aware there's 3 dungeons in the game. I'm more curious on whether iron is the "best" armor in the game, or if it goes higher than that. This really feels like a game that needs a wiki, lol.
It seems like Iron is, but I wouldn't be surprised if better gear can also be found in dungeon chests. More than likely there are higher quality rune stone and we can just upgrade or equipment. Though I don't remember if we can use rune stones on armor or not like we can on a weapon...