How to get the Thunderbolt Blade in Dragon Quest II
How to get the Thunderbolt Blade in Dragon Quest II

The Thunderbolt Blade is found deep within the Cave to Rendarak on the third floor of the Cave to Rendarak, which is only accessible after obtaining the False Idol, Eye of Rubiss and Jailor’s Key. The Thunderbolt Blade is the strongest weapon for Dragon Quest II’s Hero.

Before the details of getting your hands on this weapon, some Quick Tips:

  • Gear Up Appropriately: Give your party items like Erdrick’s Helm and Shield for your Hero, Power Shields, Erdrick’s Sword and a weapon like the Aurora Blade or Falcon Blade for your Hero and Prince, and the Lightning Staff for the Princess.
  • Quick Save Often: Collapsing floors, powerful enemies and backtracking will make having a quick slot whenever you make progress in the dungeon a must.
  • Beware The Upper Floors: You’re likely to encounter Green Dragons once you’re past the 3rd floor.
  • Retreat after getting the Blade: Leave the Cave by casting Evac, then use Zoom to rest up at the nearby village of Beran before you progress through the other side of the dungeon towards the game’s final region. 

Finding and Entering the Cave

Rendarak is the final region of Dragon Quest II: Legendaries of the Luminary Line. As such, opening the pathway to the Cave to Rendarak is a puzzling series of events that requires several the use of several key items, namely:

  • False Idol: Found in the Sea Cave, which itself requires the Temple of the Moon’s Moonshard to explore.
  • Eye of Rubiss: Requires the False Idol as well as the five Sigils scattered across the land to acquire from the Shrine of Rubiss near Dirkandor.
  • Jailor’s Key: Sold at an item shop in Burrowell as “???”, used to unlock the Teleportal to the cave.

Unlike most of Dragon Quest II’s locations, however, the Cave to Rendarak is in a somewhat isolated location. Here’s how to find the entrance:

The Teleportal you're looking for in Beran. | Dragon Quest II
The Teleportal you’re looking for in Beran.

From the town of Beran, head northwest from the inn towards this building with three doorways. Go past the priest and use your Jailor’s Key to unlock the Teleportal corridor. There will be yellow damaging tiles , but you can use the Prince to cast Safe Passage to protect yourself from the damage and continue to the portal.

On the other end of the Teleportal, head directly south and leave the building. 

How to get the Thunderbolt Blade in Dragon Quest II
Rubiss' flame outside the shrine. | Dragon Quest II
Rubiss’ flame outside the shrine.

Leave the poisoned shrine west past the oddly non-hostile Gremlin. In the overworld, talk to the flame blocking the path. As long as you have completed the quest to get the Eye of Rubiss and currently have it in a party member’s inventory, the flame will dissipate and allow you to pass through.

How to get the Thunderbolt Blade in Dragon Quest II
Unsealing the Cave to Rendarak. | Dragon Quest II
Unsealing the Cave to Rendarak.

At first glance, this poison swamp flanked by mountains seems like a dead-end. However, standing up against the northern mountain range and using the False Idol will reveal the entrance to the Cave to Rendarak. 

Path to the Blade

Make sure you go up the right stairs! | Dragon Quest II
Make sure you go up the right stairs!

From the first floor, go around this upside-down T shaped wall and head up, taking the eastern staircase.

Note: The Cave to Rendarak has many collapsing floor tiles that will send you through a pitfall to the floor below. Be sure to Quick Save now in the event that you accidentally get lost on your way to the sword.

The room you find yourself on the second floor. | Dragon Quest II
The room you find yourself on the second floor.

On the second floor, head east, going past the first two intersections. At the third intersection, head north and upstairs to the third floor.

A fork in the path | Dragon Quest II
A fork in the path
These are the stairs you're looking for. | Dragon Quest II
These are the stairs you’re looking for.

On the third floor, head northwest until you reach this fork in the path with the westward water. Head east and up the stairs once more.

The fourth floor will be a tiny corridor with stairs going up. 

Warning: The enemies on the fourth floor and beyond are some of the strongest the game will throw at you, especially the Green Dragon. To avoid losing your progress, take the time to heal up and consider making a new Quick Save slot here.

While the enemies on the lower floors are largely ones you’ve encountered in previous dungeons, below is a list of foes you might run into on the 5th and 6th floors of the Cave to Rendarak.

NameHPMPSkills
Green Dragon70NoneTorrent of Flames, Fire Breath
Berserker 62NoneNone
Killing Machine55NoneAttacks Twice
Tyrannodactyl9530 Snooze, Kasap, Fire Breath
Silvapithecus8030Sizzle, Sickly-Sweet Breath
Pitfall from floor 5 to floor 4. | Dragon Quest II
Pitfall from floor 5 to floor 4.

From the stairs you emerge onto the fifth floor. Take three steps north and one step west, you should hit a pitfall. Don’t worry, this is all part of the plan.

Your last "pit" stop on your way to the Blade. | Dragon Quest II
Your last “pit” stop on your way to the Blade.

On the area of the fourth floor that you fall into, make your way to the southwest corridor and one square north and east from the corner tile. You’ll fall into yet another hole.

The Thunderbolt Blade itself, hidden on the third floor. | Dragon Quest II
The Thunderbolt Blade itself, hidden on the third floor.

Here, you’ll find yourself just a square or two south of the Thunderbolt Blade. What luck!

If you’re feeling up to it, you can make it back to the entrance of the Cave either by making your way east from this floor and down a few more pits, or simply by casting Evac. If you’re running low on HP/MP, however, Zoom back to Beran and rest up at the Inn before you continue. 

Strength of the Thunderbolt Blade

Equipping the Thunderbolt Blade | Dragon Quest II
Equipping the Thunderbolt Blade

There’s a good few reasons to go out of your way to pick up the Thunderbolt Blade:

  • Ultimate Weapon: The Thunderbolt Blade is the Hero’s best weapon by a wide margin, giving a massive +95 attack bonus.
  • Magical Attack: Similar to items like the Aurora Blade and Power Shield, the Thunderbolt Blade can be used as an item in battle to cast Woosh on a group of enemies, at no expense. This is especially useful, since the Hero is the one party member with no Spells at his disposal.
  • Equipment Shuffle: While the Thunderbolt Blade can only be equipped by the Hero, you’ve likely had him using a weapon that would benefit the Prince. If you were previously using something like Erdrick’s Sword, an Aurora Blade or a Falcon Blade, give that sword to the Prince.