The humid heat of the forge contrasted with the cooler air of the storage shed where Carlos waited. Finally, after a few days, the potter delivered the vitrified ceramic furnaces and containers. The pieces had a dark gloss and a smooth, cold surface to the touch, exuding a slight smell of burnt clay.

  The process to extract the sulfur began. First, the pyrite was crushed until it became a granular, metallic powder that shimmered under the light. Carlos supervised each step with meticulous care.

  "First, we heat the ore between 100° and 300° to remove all moisture," he explained to Tassi, who watched with a skeptical air.

  The furnace, fueled by the controlled magic of a fire gem adept, came to life. The air around it wavered with the heat, and a dry, hot smell, like stone heated by the sun, permeated the area. When the temperature rose to between 500° and 700°, the pyrite (FeS?) began its transformation, releasing a yellowish, sulfuric vapor that slightly burned the nostrils.

  "The furnace has to be partially sealed," Carlos reminded, adjusting a ceramic lid. "If too much oxygen gets in, this vapor turns into sulfur dioxide, a gas that can ruin our lungs."

  The sulfur gas was channeled through a snaking tube into a barrel of cold water. The contact of the hot vapor with the icy water produced a constant hiss and a thick mist. Inside the barrel, shiny yellow crystals of pure sulfur began to form, precipitating like a golden powder at the bottom.

  "We just need to collect this," said Carlos, visibly satisfied, pointing to the powder.

  What remained in the furnace was iron sulfide (FeS), a dark, heavy residue. Carlos knew it still contained sulfur, but extracting it at higher temperatures would bring problems—the iron would bond with oxygen, forming oxides and more of that toxic gas.

  "For now, let's store this sulfide," he decided, examining the residual material. "It might be useful in the future, for metallurgy."

  Days passed at a rapid pace, thanks to the magical efficiency of the quilombo's artisans. The iron cauldrons ordered from Nia were quickly ready, their thick, black bottoms promising fire resistance. Carlos and Tassi wasted no time and immediately began refining the saltpeter.

  Luck was with them: the saltpeter from the guano cave was remarkably pure, which simplified the work. Even so, the process was delicate. In the first cauldron, the saltpeter was dissolved in water and heated, releasing impurities that rose to the surface like a dark, pungent-smelling foam. The saltpeter water, now cleaner, was then filtered through a thin cloth into another cauldron, where a slow, steady boil caused the water to evaporate, leaving behind beautiful white crystals of pure potassium nitrate (KNO?). Finally, the crystals were spread on straw mats under the tropical sun to dry completely, glittering like opaque diamonds.

  With the saltpeter and sulfur in hand, only charcoal was missing. Following Carlos's instructions, they gathered soft, light woods from the dense forest surrounding the quilombo. The sweet, woody smell of freshly cut firewood filled the air as they prepared the carbonization.

  In a clearing in the forest, Carlos asked Tassi:

  "We need a shed here, to be our gunpowder workshop. Something simple, but covered."

  With the help of her magical gem bracelets, Tassi manipulated earth and wood with impressive dexterity. In no time, a rustic but functional structure stood, shaded by the tree canopies.

  Inside the new workshop, Carlos revealed the recipe.

  "Black powder takes saltpeter, sulfur, and charcoal. In the proportion of 75% saltpeter, 15% charcoal, and 10% sulfur."

  The three powdered ingredients were carefully mixed in a large wooden bowl. The mixture was then moistened with a solution of water and a bit of cacha?a, forming a dark, lumpy paste that smelled of sulfur and earth.

  "The moisture keeps it from exploding while we handle it," Carlos explained, seeing Tassi's dubious expression.

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  The subsequent work was exhausting. The wet paste was pounded for hours on end with a wooden pestle, then pressed to compact it, crushed again, and finally sifted to obtain uniform grains. The grains were then set to dry on shallow trays outdoors.

  The process was so laborious that Carlos ended up asking Pedro and others from Jorge's engenho for help. Having been freed by him, they showed themselves willing to collaborate. Carlos asked Aqua for permission, who, after some consideration, authorized the help, keeping the newly freed under observation.

  After a few weeks of hard work, they had produced enough gunpowder to fill several clay pots. Carlos conducted quality tests in an isolated spot, away from prying eyes. The dull thud and the cloud of smoke that followed confirmed his success. He deliberately did not take Tassi to these tests.

  "Finally!" he exclaimed, charcoal powder darkening his hands. "We have enough gunpowder for a good demonstration. I think we can show the Specter. I'm sure he'll see the usefulness in this. And I was thinking... we can use this to make a trap for that Boitatá that attacked us."

  Tassi observed the black powder with skepticism. She didn't see much danger in the granular substance, despite all of Carlos's precautions—working only with wet gunpowder, avoiding metal tools to prevent sparks.

  She frowned, suspicious.

  "And the explosion this makes... is it really that strong?"

  "You'll see," replied Carlos, a confident smile on his lips. "I did some tests in secret. This gunpowder is good quality. It's going to be one hell of an explosion! Let's call Aqua and the Specter. And Quixotina, since she helped us. And it would be good to have someone who uses fire gems, like Nia. I bet she'll be interested."

  Tassi gave a mischievous smile.

  "I bet you just want to show off for her, huh? You really want to be her fifth husband, don't you?"

  "Not at all!" he protested, blushing slightly. "And at least she can get someone! What about you? There are so many single men here, finding a husband should be easy, but you're still 'unmarried,' right? I at least have the excuse that I'm not from here."

  Tassi was irritated by the comment but didn't show it, merely retorting coldly:

  "I don't want to be tied down. But that's not why I'm not seeing anyone. At least I've been with more people than you!"

  Carlos was surprised by her frankness but quickly regained his composure.

  "Of course! The competition for any woman here is very high. Not to mention, I'm not from the same world as the women here. I don't really know how to approach them. Anyway, enough chit-chat. Go notify Aqua and the others about the gunpowder demonstration, tomorrow afternoon. I'll prepare everything. Oh, and I have to talk to Nia, to see if she can do something with the fire gems."

  Tassi smiled mischievously again.

  "Sure. I'll call everyone, and you call Nia."

  Carlos rolled his eyes and went out to prepare the gunpowder for the demonstration. With great care, he filled a large clay pot with the black grains. Then, he headed to the blacksmith's workshop.

  The rhythmic sound of the anvil echoed through the clearing. He knocked on the wooden door. Moments later, Nia opened it, her face gleaming with sweat and her hair tied up haphazardly. The intense heat of the forge enveloped him like a cloak.

  "Good afternoon, Nia. The other day, I saw you throw some fire gems under the furnace and, after a while, they activated. I need your help for tomorrow; I want more of those gems. Can you prepare some gems to make a remote explosion with the gunpowder?"

  Nia wiped her hands on a dirty rag, studying him.

  "I should complain about you disturbing my work, but... how interesting. You had this idea just from seeing me throw the gems into the furnace? I can indeed make them activate after a delay. Actually, you can do that with any gem, but each one needs a specific carving for the same effect. And other gems aren't as easy to work with as fire gems. Anyway, how much time do you need for the activation?"

  "So that's how it works? How interesting," Carlos marveled. "But I don't understand the logic behind it. How does something carved into the gem alter the power it displays?"

  "Only the Orixás must know the reason for that," Nia replied with a shrug.

  "About the gem."I think if it could activate after five minutes, it would be perfect."

  "Five minutes? How long is that?"

  "Ah, sorry. It's a time standard from my world. Let's say... enough time to walk a good distance calmly and come back to hide."

  "Hmmmm, I see," Nia murmured, looking at him with renewed suspicion, but also with a glint of curiosity in her eyes.

  The blacksmith's distrust left Carlos a little frustrated.. Everyone thinks I'm crazy for saying I'm from another world. I guess I should have hidden that information. It's a shame I'm terrible at lying... But they'll see! There will come a day when I bring so many changes to this world that it will be undeniable that I come from elsewhere. And the first thing that will transform everything is gunpowder.