Ultimate Key Door Locations - Dragon Quest 5

You can begin the quest for the Ultimate Key at any point after gaining control of the Zenithian Hero (aka your children) during the third generation/chapter of the game. Head to Mostroferrato and speak with Mr. Briscoletti in his mansion and he'll ask you to head over to the island west of Stockenbarrel (pictured above) to check on the color of an urn.

Once you inspect the urn head back to Mostroferrato and a guard will tell you that Briscoletti is in the tower right next to town. Make sure you're prepared before heading to the top of the tower because once you speak with Briscoletti up there you'll begin the boss battle with Bjorn.

Prior to fighting Bjorn it is highly recommended that your Hero is at least level 30 and your kids (if you are using them) are at least in their mid 20s. Having a Slime Knight, Cureslime or any other monster that can heal in your party would be a giant help for this upcoming fight as well.

Use Kabuff on your party if you have it as well as Insulatle/Insulate if you're using your son. I highly recommend you bring your daughter too since she is able to Kasap the boss which is very important. Your daughter also has the Oomph spell which is another amazing buff to use on your phyiscal damage dealers. Buffing your party and debuffing your enemies is extremely important in the Dragon Quest franchise and it does more than in other RPG games.

Every time that Bjorn uses his Buff ability 'Use' the Zenithian Sword as an item during battle to dispell it. What this fight boils down to is you constantly using Kabuff on your group to offset the bosses Kasaps as well as you using Kasap on the Boss to offset his Buff ability (and Using the Zenithian Sword to remove his Buff ability if he stacks it high enough).

Much like all of the harder bosses at this point in the game Bjorn will get two attacks each round and if you're really unlucky he can focus someone in your group down in a single round. In these situations sometimes the only thing you can do is restart the fight or level up your characters more.

After defeating Bjorn you'll be rewarded with the Ultimate Key for your efforts. If you married one of Mr. Briscoletti's children (Nera or Debora) then speak with his wife after the battle to receive 5000G coins. Now that you have the Ultimate Key you're able to travel around the world and open all the different locked doors using it.

Below you'll find locations of every locked door that the Ultimate Key will open in Dragon Quest 5.

 

 

#1 Dominicus' Dominion Ultimate Key Door

Items: Mini Medal, Golden Tiara and Mini Medal

On the right hand side of the Dominicus' Dominion castle you'll see a set of stairs that go down into the basement, the zone is very small and it's difficult to miss. There are 3 chests for you to steal in here behind a metal door.

 

#2 Gotha Castle Ultimate Key Door

Items: Prayer Ring, Robust Lingerie and Happy Hat

Approach the church at the northern end of the castle's first floor. Instead of going up the stairs into the church go right and through the door into a hallway (pictured above). Use L and R to rotate the camera in this hallway to reveal the door next to the stairs.

 

#3 Ancient Ruins Ultimate Key Door

Items: N/A

This door is found in the Ancient Ruins east of Coburg, it's the same door in the area where Pankraz told you to flee on the raft as he held back enemies. There is nothing to find here though so there is no point in coming here unless you want to open every single door with the Ultimate Key.

 

#4 Fortuna Jail Ultimate Key Door

Items: Mini Medal

You can find the Fortuna Jail to the right of the building that sold you the Wagon earlier in the game. You'll see a set of stairs that go down on the other side of the wall that leads to the Fortuna Jail. Note: This is the same location you had to come for the Magic Key Locked Door too.

 

#5 Crocodilopolis Ultimate Key Door

Items: Serf Wear, T 'n'T Ticket (left watch tower) and Zenithian Armor (right)

Crocodilopolis is found on the northern tip of the central continent on the World Map and you'll need the Zenithian Dragon in order to reach it. Once you land here you will want to use L and R to spin your camera around so you can see the doors that lead into the watch towers. In each watch tower there is a metal door that you can unlock with the Ultimate Key that will lead to goodies. The Zenithian Armor is in the watch tower on the right.

If you are having trouble locating Crocodilopolis I recommend you visit Chapter 9 of my Walkthrough, the first picture on that page is the map location of Crocodilopolis.

 

#6 Mantleplace Ultimate Key Door

Items: Elfin Charm, Mini Medal, Hela Hammer, Pallium Regale

Mantleplace is one of the optional dungeons of the game which can only be accessed once you have acquired the Ultimate Key. You'll find the cave which houses this dungeon almost directly north of Roundbeck. The way this dungeon works is you have to cover a hole on the ground with a boulder to stop monsters from spawning on each floor. Once you've covered the holes on all 4 floors you'll be able to obtain the Pallium Regale on the platform on the 4th floor of the dungeon.

 

#7 Estuary Sanctuary Ultimate Key Door

Items: N/A

This Ultimate Key Door is used in the storyline of the game and you will open it on your visit to Nadiria. To reach this location you'll want to Zoom to Lofty Peak and hop in your ship to travel north up the river. When you zone into Estuary Sanctuary keep going north until you dock in front of a temple (pictured above).