Dragon Quest IV Ultimate Key Door Locations
This guide is a list that contains the locations of every door that you can open with the Ultimate Key in Dragon Quest 4. You'll receive the Ultimate Key during Chapter 5 when you visit Femiscyra, a town surrounded by mountains in the east.
If you'd like to see the locations of Magic Key/Thief's Key locked doors, follow the links below to be taken to those guides instead.
List of Locked Blue Doors (Thief's Key)
List of Locked Red Doors (Magic Key)
Strathbaile Prison Mini Medal
This Mini Medal requires the Ultimate Key to reach, luckily Strathbaile is on our Zoom list so it's not all that out of the way getting here. If you've forgotten where the Strathbaile Prison is, it's in the northeastern part of town in the "alley way" between the Church and armor/weapon shops. The Mini Medal is in a pot in the cell.
Items to Find:
Mini Medal
Ballymoral Prison Cells
Zoom over to Endor and travel north to Ballymoral, during the day time enter the Ballymoral castle and go down into the prisoner area. Two guards patrol around this place that you will have to dodge the entire time, but there are plenty of goodies that make this inconvenience worth it.
Note: Make sure you rotate the camera while you're inside here, much of the treasures are hidden out of sight unless you do.
Items to Find:
Horse Manure
Mini Medal
Seed of Magic
Seed of Life
Casabranca in the Castle
This is the first real town that you come across when you start the Hero's chapter. It'll probably be the first town on your Zoom list which makes traveling back here a piece of cake. You'll find the large metal gate to unlock in the northwestern portion of the castle.
Items to Find:
Prayer Ring
Mini Medal
350 Gold
Porthtrunnel's Inn
Zoom over to Porthtrunnel and head to the Inn. Upstairs you'll find a large metal door which you can open with the Ultimate Key. Inside is a Treasure Chest which contains a massacre sword.
Items to Find:
Massacre Sword
Lakanaba - Torneko's Home Town
In the same Weapon Shop that Torneko worked in when we did his Chapter if where you'll find these Treasure Chests. Go down into the basement and there is a locked metal door right in front of you with three chests inside.
Items to Find:
Chain Sickle
Seed of Strength
Icicle Dirk
Havre Leon - Prison Cells
In the northeastern part of Havre Leon, the unmarked building with only a single basement is where you will find the prison cells in this town. Smash each of the pots in the three prison cells to collect all of the loot here.
Items to Find:
2 Mini Medal
Seed of Strength
Vrenor Cave - Lightning Staff
In the bottom of Vrenor Cave where you found the Sparkly Bracelet the first time here you'll now find a switch in the bottom of the same Treasure Chest. It'll create a staircase that leads down into another part of the dungeon which was previously unaccessible.