the bandit hideout protected with spike, how to pass it?
You'll need to talk to a particular noble in the city to unlock the bandit hideout. Warning: If you go for the bandit hideout before doing the noble corruption quest and beat the bandits, you lock yourself from the scene. It'll give you tickets for the scenes, though. The game warns you when you go into the hideout. It gives you the major upgrade for the weapon (third one)
where to find gold eye for first wand upgrade
That's the boss for the first dungeon, the forest dungeon.
who drop iron?
and i think i miss a quest where i need to slay subspecies monster in poison bog area
The iron drop is in the underground dungeon, which I consider the second dungeon. It's the one south to the forest, on the side with the noble's city instead of the side closer to the starting town. The goblins, if I remember correctly, drops them. You'll find the quest for the poison bog area in either in area with hotspring or the noble's city. I don't remember which.
Depends on what you want a guide on? If it's the endings, someone in this thread mentioned it earlier. As for walkthrough or guide... the game is honestly quick enough that you can get to the castle in under an hour if you are going corruption route. I don't know if the earlier threads would mention where all the different locations for the different h scenes are. I know they do have some of that though.
