Feng Che had indeed learned through the memory of the Spider Ninja that the "Fortress of Venom" on the surface was merely a decoy to distract the World League. Hanzo Shura's true lair was buried deep underground.
This subterranean labyrinth consisted of thousands of tunnels where countless Poison-type Pokémon fought for survival. Hanzo's training method was akin to "Gu" sorcery—trapping Pokémon of the same species in sealed caves and forcing them to slaughter one another for food until only the strongest remained. These survivors were then drafted into his elite army, bound by his unique insect-commanding arts.
"The World League can destroy my castle," Hanzo muttered to himself in his inner sanctum, "but they won't find my shadow. As long as I escape with the Poison Dragon's Scale, I can rebuild everything."
The scale was sealed in a specialized heavy alloy container. It was so immensely heavy that Hanzo had to pay a fortune to General Greya to use her psychic powers just to move it to the island.
Feng Che hovered above a stream of bubbling purple liquid. The tunnels were illuminated by a carpet of fluorescent violet moss. This toxic vegetation grew at an incredible rate, serving as the primary food source for the underground denizens.
"I feel the pressure of a Mythical being here," Mewtwo said, searching his ancestral memories. "A Poison-type god... who could it be?"
"If I'm not mistaken, this is the lingering aura of the dragon that sleeps beneath Galar," Feng Che explained, pointing upward. "The dragon from outer space—Eternatus. It is the source of the Dynamax phenomenon and arguably the most powerful Poison/Dragon-type in existence."
Suddenly, a heavy sliding sound echoed through the tunnel. Hundreds of Seviper and Arbok emerged from the shadows, their crimson eyes flashing with hunger.
Seviper: It's been so long since we had fresh meat...Arbok: This human is mine. I must strike before the Ariados colony realizes he's here.
The snakes parted as a massive Seviper, nearly three times the normal size and covered in jagged scars, slithered forward. Its blood-red fangs glistened in the moss-light. This was the colony leader, and its predatory instincts were screaming.
"Quite the welcome committee," Feng Che sighed. "Decidueye, I'm counting on you."
In these cramped, gas-filled tunnels, few Pokémon could fight effectively. Feng Che also released Poipole. Since this was a sanctuary of toxicity, Poipole could absorb the ambient energy to grow stronger.
"Poipole, use Poison Sting! Decidueye, Leafage!"
A green flash flickered in Feng Che's shadow. Thrum. The faint vibration of a bowstring preceded an Arbok collapsing with a green quill-feather buried in its skull. One by one, the snakes were picked off with mechanical precision.
Suddenly, a frantic skittering sound came from the rear. Thousands of Ariados, the size of millstones, began to seal the tunnel with thick, grayish-white webbing. Their sharp silk pierced through the scales of the remaining Arbok and Seviper, dragging them into the nets. The snakes thrashed, but the venomous silk only widened their wounds.
The massive Seviper leader prepared to roar a command for a counter-attack, but it froze. A rhythmic Thump... Thump...—like a drumbeat—vibrated through the walls.
A Two-Headed Ariados emerged from the darkness.
The Seviper leader's pupils shrank. Without a second thought, it abandoned its kin and fled into a side tunnel. It knew all too well how many "Kings" of this pit had been devoured by this twin-headed nightmare. The mutated Ariados, freshly awakened and ravenous, lunged forward, its claws instantly impaling a stray Seviper through the brain.