Culex is Super Mario RPG’s hidden boss and is meant to be a challenge for players looking for more battles. You will only be able to reach Culex once you have collected the Shiny Stone and made it to Monstro Town. Once there, you can find him and his four crystals waiting for you behind the mysterious black door. The guide below goes over how to unlock Culex and how to defeat him in battle.

Where to Find The Culex Secret Boss¶

Culex is located in Monstro Town right next to the Item Shop. He’s inside of the ominous black door that refuses to open. If you want to get inside, head to Moleville. Here, you will find a young mole hiding behind some boxes in the center of town. She tells you that she has a Shiny Stone and will trade it for fireworks. Go into the house to the left of her. Here, you will find a mole working at a counter in the corner. When you speak with him, he will sell you the fireworks for 500 coins.

Take these back to the girl to get the Shiny Stone. You will now want to return to the door in Monstro Town and interact with it. This time, it will let you inside to fight Culex. We do recommend you are over level 20 before taking on this fight. Culex is a secret boss with a brutal range of attacks and four helpers that will all work to take your party down.

Best Party for Culex¶

During your fight with Culex, you will need to switch between Geno and Mallow to use attacks that the crystals are weak against. Geno is great for buffing Mario, though, using Geno Boost, especially if you can use the action command to gain the defense buff. Culex does have shredder which will remove buffs, so you will need to switch Geno back in from time to time. Peach is always needed on your team as you take a lot of damage in this fight, and your party will need to be healed and revived throughout the fight.

Best Equipment For Culex¶

Mario¶

Geno¶

Peach¶

You will want to pick items that ensure you stay alive, especially in the case of Peach who is your healer. Mario can use the Attack Scarf to give him an extra boost, as he will need it to deal with the two crystals who are weak to his Jump and Fireball attack.

Culex - Stats and Weaknesses¶

The Water Crystal is weak to Fire, so use Mario’s Ultra Flame, and the Fire Crystal is weak to ice, so use Mallow’s Snowy. Once you are down to Culex himself, unleash everything you have, but ensure you can still heal yourself with Peach, as Culex can do quite a bit of damage on his own. Once you win the fight, you will know as Culex shudders and then disappears as the Final Fantasy fanfare begins to play.

Culex - Attacks and Special Abilities¶

Fire Crystal Attacks¶

Water Crystal Attacks¶

Earth Crystal Attacks¶

Wind Crystal Attacks¶

Culex Attacks¶

As you can likely see, there are a lot of attacks to contend with. Each crystal has its own list of different attacks, as does Culex. What’s important here is picking up on the attacks that can be blocked and which ones you will need to suffer through. There are also a couple of attacks that cause status effects and debuffs. These are Culex’s Shredder, the Winder Crystal’s Light Bubble, the Earth Crystal’s Sandstorm, and the Wind Crystal’s Petal Blast. Shredder will take off any buffs you have, while Light Bubble can put party members to sleep. Petal Blast is a very common move that’s often seen in the early turns of the fight, and it can turn party members into a mushroom. Be sure to use Peach’s Therapy or Group Hug to heal these afflictions.

Culex - Rewards¶

For defeating Culex, you will receive the Quartz Charm. This is an accessory that will give you a 50% attack buff on the character who equips it. Additionally, once you reach the post-game and complete all boss rematches, Culex 3D, the game’s ultimate boss, will unlock.