Culex

"I am matter... I am antimatter... I can see your past... I can see your future... I consume time... And I will consume you!"

- Culex

Culex is an optional hidden boss who appears in Super Mario RPG: Legend of the Seven Stars. Alongside the Crystals, Culex is an even more powerful boss than the main story's antagonist, Smithy. His alignment and motives differ drastically between the Japanese and English versions.

In the Japanese version, Culex claims to be a timeless overlord made of pure evil. As a two-dimensional being, he is perplexed by the three-dimensional forms of Mario's party, so he demands a fight to try and understand them. Upon defeat, he recognizes the party's strength and positive energy, and he and his pocket dimension disappear to parts unknown until the day he finally gains the solidity of the third dimension. In the English version, Culex's dialogue and backstory are completely rewritten: he is said to be a "Dark Knight of Vanda" sent by the Dark Mage. He has nobler mannerisms, and attempts to leave Mario's company on good terms.

History
Before or during the events of Super Mario RPG: Legend of the Seven Stars, Culex comes to reside in a cross-dimensional region found behind a sealed door in Monstro Town. According to one of his neighbors, a Piranha Plant, Culex is "always mumbling about Crystal-this and an Evil-that." The Piranha Plant also provides a clue to opening the sealed door, telling Mario about Culex's obsession with Crystals, and then hypothesizing: "Isn't a “Crystal” some kind of a shiny rock...or something? I know I've seen those somewhere!" This hints at the Shiny Stone. To retrieve a Shiny Stone, Mario must first buy the Fireworks from a male mole in Moleville for five hundred coins, then trade the Fireworks for a Shiny Stone from a young mole girl in the same town. With the Shiny Stone, the door reacts and the seal is removed. Upon entering, Culex greets Mario and explains his story. He then challenges Mario to a battle, which the player can either accept or refuse.

In battle, Culex is aided by four Crystals – the Earth Crystal, the Fire Crystal, the Water Crystal, and the Wind Crystal. Each Crystal has command over potent magic attacks aligned with their elemental power. Culex himself is a powerful warrior with 4,096 HP, the second most of any encounter in the game (behind only Smithy's second phase). The group as a whole has 12,396 HP, which exceeds both of Smithy's phases combined. All four Crystals can be defeated independently before targeting Culex, but if Culex falls, any remaining Crystals shatter one by one on their next turn.

If Mario's party is victorious against Culex, he will reward Mario with the Quartz Charm. Culex then leaves Mario's dimension as Mario is transported back to Monstro Town. The door to Culex also vanishes, leaving a solid rock wall in its place. The Piranha Plant next door thinks "our neighbor moved away."

At Bowser's Keep, one of the questions Dr. Topper can ask when he quizzes Mario is what Jinx, Goomba, and Culex have in common. The correct answer is: "They live in Monstro Town."

Allusions to Final Fantasy
Culex stands out in the game for being an allusion to the conventions of the  series.

Culex has two different sets of game sprites, one for the overworld and a much larger one for battle, resembling the enemy design in the 2D Final Fantasy titles. Super Mario RPG: Legend of the Seven Stars enemies (except for Valentina, Shelly, Jonathan Jones and Magikoopa), on the other hand, have the same sprite for both the overworld and for battles. In the style of early Final Fantasy games, Culex's battle sprite is rendered as a two-dimensional sprite that does not change when attacking or being attacked, in contrast to the pre-rendered sprites of all other enemies in Super Mario RPG, which have complex animations when attacking, being attacked, and walking in place. In the Japanese version, Culex himself makes extensive note of the discrepancy in art styles.

The four Crystals used by Culex in battle are also based on the important reoccurring artifacts from the Final Fantasy series, appearing in many entries in the series with different functions in each. All four Crystals featured in the battle are from the original  for the Nintendo Entertainment System, although they did not gain their unique coloration until much later in the series. This connection is heightened by the Japanese name of the Quartz Charm, which is the Crystal Charm.

Moreover, the three music tracks associated with Culex are covers of three music tracks from the Final Fantasy series. His battle music is a cover of the boss battle theme from  (initially Final Fantasy II in North America), the music that plays when he is defeated is a cover of the victory music present throughout the Final Fantasy series, and the ending conversation is a cover of the Final Fantasy "Prelude".

Quotes

 * For a full list of quotes, see here


 * "Greetings. I am Culex, Dark Knight of Vanda. I've crossed into this dimension to fight for the Dark Mage. But this world is uninhabitable for me and my kind. I must return to my own world. Before I go, though, I would like to challenge your strongest knight. Will you accept my challenge? You will enter combat against me?"
 * "You are wise to hesitate. Without any weapon or armor, you have no chance."
 * "En garde!"
 * "I am matter... I am antimatter... I can see your past... I can see your future... I consume time... And I will consume you!"
 * "A little off, eh?"
 * "Perhaps in another time, another game, we may have been mortal enemies... Let us part as comrades in arms."
 * "Take this. Treasure it as a keepsake of our fight."
 * "Farewell, champion knight!"