Super Mario RPG: How To Unlock & Beat The Final Superboss

Welcome to our post-game guide for the Super Mario RPG remake on Nintendo Switch.

Once you've defeated all of the optional bosses in the Switch version's post-game, there's one final challenge waiting for you at the end of the road — and it's not an easy one.

In this guide, we'll tell you how to unlock the brand new superboss, what level you should be, and how to defeat Super Mario RPG's toughest boss fight.

Note: This guide contains major spoilers for the post-game, so if you want to maintain the surprise, make sure you head back to our hub guide.

Super Mario RPG: Post-Game Guide - Final Superboss

How to unlock the final superboss

The conditions to unlock the final superboss are pretty straightforward. All you need to do is defeat all six post-game boss rematches and get the Extra-Shiny Stone.

That means you need to have beaten the final boss and rolled credits, stayed at the Marrymore Hotel suite, visited Star Hill, and spoken to the Frog Sage at Tadpole Pond to find out what certain NPCs are doing across the world.

If you haven't defeated all of the bosses, we have guides for each of them below. In addition, you will get the Extra-Shiny Stone from one of these fights automatically:

• Belome Rematch
• Punchinello Rematch
• Booster Rematch
• Bundt Rematch
• Jonathan Jones Rematch
• Jinx Rematch

Once you've acquired the Extra-Shiny Stone and beaten all six bosses, go back to Tadpole Pond and speak to the Frog Sage, who will tell you about one more NPC that you've previously faced.

Where to find the final superboss

If you've figured out who this extra challenger is by now, you should have a good idea about where to go — Monstro Town.

If you go back there, you'll notice that a certain door has reappeared in the middle of the wall. Approach it and the Extra-Shiny Stone will react. Then you can enter if you dare.

Note: This is your final warning — if you've scrolled this far through a 'final superboss' guide but still don't want to know its identity...what are you even doing!?

Here we go!

How to prepare for 3D Culex

There are a number of things you can do to make this tough challenge that little bit easier.

Stock up on items

Bring all of the healing items you can to this fight, because there will be times where you can't rely on Peach's healing spells. Pull them out of your Storage, buy them from the Tadpole Pond shop (Croaka-cola is fantastic, but Finless Cola is great, too).

Use your best items

We don't just mean healing items, here. If you have any Rock Candy or bombs left, then this fight is a good place to use them. The Rock Candy in particular does a lot of damage to enemies.

Max out your party's levels

You don't have to do this, but we would recommend being level 28 and above. Level 30 is preferable, but this fight is doable under the maximum level.

Get the best equipment

This is a no brainer, and if you've completed all of the post-game bosses, you should have Geno, Mallow, and Bowser's best weapons. Peach's can be bought in Moleville from the Toad treasure-hunter, while Mario's is part of a short sidequest to get the Lazy Shell.

In terms of armor, the Lazy Shell armor is great for Peach. if you're a Super Jump pro, then you can do 100 Super Jumps to get the Supersuit. Otherwise, the armor you can buy at Bowser's Keep from Croco is the next best.

Accessories such as Jinx's Belt, Feather, Safety Ring, and anything that boosts attack and defense is great for this fight.

Max out your Attack Gauge

So you're not worrying about this during the fight, you should make the time to max out your Attack Gauge so you have immediate access to a Triple Move. You won't use it right away, but it's not bad to have ready, especially with Culex's new Meteor spell.

Heal up

This seems like a silly thing to suggest, but heal your characters up before you enter the fight. If you don't, you'll lose a character immediately and have to waste a turn reviving them.

How to defeat 3D Culex

Recommended party: Mario, Geno, Peach

Culex is back, and he finally made it into the third dimension. That also means that this fight is harder than the first round, but the basic tactics essentially remain the same here. That means, once again, don't waste any turns on Geno Boost or Bracers, as the Culex's shredder will nullify buffs.

The biggest difference here is that we highly recommend taking out all four Crystals this time around. They do a lot more damage this time around and can be a nuisance when dealing with Culex himself. Fortunately, at this point, you should be very good at timing your attacks and dealing splash damage. Alternatively, you could use Mario, Geno, and Bowser's Triple Attack, but we're looking for the defensive buffs here.

There's a catch to this, though: every time you destroy a Crystal, Culex will get a buff depending on which one you defeated — the Red increases his Attack, Blue his Magic Attack, Yellow his Defense, and Green his Speed. The stat buffs are much easier to deal with than the onslaught of attacks from the Crystals.

When the fight begins, Culex will immediately cast Meteor, a powerful spell that attacks all party members and reduces their health to 1. As long as the Crystals are alive, Culex will continue to cast this every five rounds, where you'll see a countdown timer in the top right corner. If any of your characters are below max health, they will be immediately knocked out by this. It's essential to keep your party's health topped up, particularly right before Culex casts the spell.

You can't stop Culex from casting Meteor, but if you're not at max health and can't heal up for some reason, you can use Mario, Geno, and Peach's Triple Attack to completely nullify the attack's damage.

Throughout the fight, one of your action buttons will be disabled, just as it was in the Bowyer fight. That means that you might not be able to use Items or Special attacks at certain points. This is why we recommended topping up on Items, just in case Peach can't heal with her Specials, or in case you need to burn through more Special attacks to deal damage. You can also use Rock Candy here to deal a huge amount of party-wide damage to the enemy. When you defeat the Crystals, you don't need to worry about this anymore.

As with the regular fight, each Crystal represents an element and will attack you with that element. You can use Geno Flash to do damage to all of the enemies, but we'd recommend using FP for healing as much as you can. Instead, have Mario and Geno do regular attacks, and Peach focus entirely on healing. We went from Fire, Water, Wind, then Earth but it doesn't matter what order to defeat them in.

Once you've taken down all four Crystals, Culex will be able to attack twice per turn, and he will also have a new attack that he can use after the timer counts to 0 — Fatal Claw, which does 9999 damage. Not even the Lazy Shell can protect against this, so you'll just have to revive your character or rely on that Triple Attack from Mario, Geno, and Peach.

You might want to swap Peach out for Bowser, who can dish out a lot more damage than the Princess. You can use items to heal if needed.

The second phase should be much more straightforward in general. Culex's attacks are fairly easy to block — except for the ones you can't block. It'll take a while, but eventually, you'll come out on top.

3D Culex reward

After you've defeated 3D Culex, he will tell you how many turns you took to defeat him and give you a Crystal Shard as proof that you've beaten Super Mario RPG's hardest boss.

For more help on getting through Super Mario RPG, check out our full Super Mario RPG guide for everything you need.