Before entering the cave, Sato released the two Pokémon he had only temporarily captured—Geodude and Taillow—back into the wild. Before sending them off, he also gave them some delicious Pokémon food.
He then released Swampert and had it clear away the pile of rubble blocking the cave entrance. Afterward, he instructed the Pikachu on his shoulder to use Flash. Once his eyes had adjusted to the light inside the cave, he led his Pokémon deeper through the tunnel.
The gigantic Steelix was unquestionably the overlord of this area. No wild Pokémon dared to enter its territory, so with the giant Steelix now gone, Sato's journey through the tunnel was completely uneventful.
Along the way, he kept a close eye on the special detector he had seized from one of the Team Magma grunts, carefully watching the changes in the indicator lights.
As he ventured deeper into the cave, Sato gradually began to feel the temperature rising. It was obvious that the tunnel dug by the Steelix sloped downward into the earth. The growing heat could only mean one thing—he was approaching the magma layer.
Sure enough, after walking another seven or eight minutes, the tunnel suddenly opened into a vast underground cavern. At the center of this enormous chamber lay a massive lake of molten lava radiating terrifying heat.
"So this was Steelix's sanctuary. Back when it was still an Onix, it probably tempered its body with the heat from this lava lake. And this was also its dining hall."
Looking at the deep grooves carved into the shoreline and the chunks of lava rock that had clearly been gnawed on, Sato quickly deduced why Steelix had chosen to make its nest here.
The lava lake not only helped Steelix temper its body, but the cooled lava was rich in minerals, making it the perfect food source for a Pokémon that fed on rocks and earth.
A place where it could strengthen itself while simply lowering its head to enjoy delicious food...
This truly had been Steelix's paradise.
The underground chamber was oppressively hot. Sato had only stood there for a short while before sweat poured from his body, soaking his clothes.
"I need to find Groudon's Blood as quickly as possible. Otherwise, I'll probably die of dehydration if I stay here much longer."
He wiped the sweat from his forehead with a handkerchief while frowning at the detector in his hand, whose red light was flashing continuously.
"Pika... Pika..."
The Pikachu on his shoulder was already panting from the heat, looking completely drained. Even so, it stubbornly refused to return to its PokeBall.
Swampert, on the other hand, was perfectly fine. The mutated Supreme Blue Water Stone within its body constantly maintained an Aqua Ring around it, giving it tremendous resistance to the oppressive heat.
As for Kecleon, it had long since used Flamethrower, then utilized its Protean Ability to temporarily change itself into a Fire-type, greatly increasing its heat resistance.
The ground of the cavern was scorching hot, becoming even hotter the closer one got to the lava lake. Left with no alternative, Sato used his telekinetic psychic powers to levitate himself above the ground as he searched along the edge of the lava lake for Groudon's Blood.
However, trouble soon found him.
A large number of Slugma and Magcargo actually lived within the lava lake.
These wild Pokémon seemed to serve as the guardians of Steelix's sanctuary. The moment Sato approached the lake's edge, they launched an attack from their hiding places within the molten lava.
In an instant, a tremendous wave of searing flames swept toward him, leaving him nowhere to dodge.
Fortunately, Sato had remained vigilant. Swampert immediately stomped the ground with its right foot, raising an earthen wall that bought them a brief moment. Using that opening, Sato instantly teleported himself and his Pokémon away.
But no sooner had they escaped than wave after wave of awakened Slugma and Magcargo crawled out of the lava lake, surrounding Sato from every direction as though determined to drive him away.
"So if I want to find Groudon's Blood here, I'll have to defeat these guardians first."
Frowning, Sato immediately issued an order to the eager Swampert beside him.
"Swampert, use Earth Power. Clear them out."
During his time on the mysterious island, Sato had learned one important lesson. Wild Pokémon thought completely differently from humans.
Kindness and generosity were never the keys to earning their respect. Only overwhelming strength would make them acknowledge you.
Simply put, in the eyes of wild Pokémon, the one with the stronger fist was always right.
"Swamp!!"
Swampert roared loudly before slamming both fists into the ground.
Instantly, numerous earthen pillars erupted from the earth in a fan-shaped pattern.
In the blink of an eye, a huge swath of Slugma and Magcargo was blasted into the air by the pillars created by Earth Power. They then rained back down like falling dumplings, crashing to the ground unconscious.
Although there were countless Slugma and Magcargo, most were only around level twenty. How could they possibly withstand Swampert's wide-area Earth Power?
With a single attack, Swampert cleared an enormous section of enemies.
Unfortunately, the lava lake housed an immense population of Slugma and Magcargo. As soon as one wave was eliminated, countless more emerged from the molten lake to fill the gap.
Swampert had followed Sato through the mysterious island and had long grown accustomed to being besieged by hordes of wild Pokémon. Faced with enemies that refused to retreat, it showed no fear whatsoever, repeatedly unleashing massive Earth Power attacks.
Pikachu also joined the battle.
Thick bolts of electricity burst from its body, specifically targeting the higher-level Magcargo.
Both Slugma and Magcargo possessed extremely poor Special Defense. Pikachu's Electric-type attacks were devastating, and the lower-level Magcargo stood no chance, each one falling after a single hit.
Before long, Swampert and Pikachu had worked together to wipe out wave after wave of Slugma and Magcargo.
As more and more of their kin fell, the lava-dwelling Pokémon finally realized that sheer numbers alone could not defeat the enemy before them.
The problem was that they couldn't even get close enough to attack.
Their long-range fire attacks were effortlessly blocked by the earthen walls Sato's side continuously created.
Meanwhile, their opponent seemed to possess inexhaustible strength, unleashing move after move without showing the slightest sign of fatigue.
Finally, a level 69 Magcargo emerged from the lava lake leading five other Magcargo above level 60.
They charged forward with tremendous momentum...
...only to be instantly wiped out by a single Earth Power from Swampert.
After that, not another Slugma or Magcargo dared emerge from the lava lake.
"SWAMP!!"
Perhaps disappointed that the battle had been so one-sided, Swampert let out another thunderous roar toward the lava lake after seeing that no more opponents would appear, venting its frustration while openly provoking them.
Unfortunately, after witnessing so many of their comrades fall, the remaining Slugma and Magcargo had been thoroughly frightened.
They all hid beneath the lava like turtles withdrawing into their shells, refusing to come out again.
"They're afraid now. Good."
Standing at the junction between the tunnel and the underground chamber, Sato raised his voice.
"Listen well. As long as you don't interfere with me, I won't interfere with your lives. I'm only here to find one thing. Once I have it, I'll leave."
His voice echoed throughout the eerily silent cavern.
Sure enough, after first displaying overwhelming force and then offering peaceful terms, not a single additional Slugma or Magcargo dared emerge from the lava lake to interfere with Sato's search for Groudon's Blood along its shores.