The light blue body of Mudkip gradually began to change.
Originally standing at only forty centimeters tall, the Pokémon grew visibly under the glowing aura of evolution. The three thorn-like yellow whiskers on its cheeks slowly fused into one, while the fins on its head and tail darkened in color. The rounded head fins sharpened into distinct spikes, and Marshtomp, which once moved on all fours, gradually rose onto its hind legs, adopting an upright posture. Its blue skin shifted into a deeper hue, blending shades of blue and green.
Tiny red veins—like energy pathways—rippled across its body, searching for the optimal points to enhance its form. Each time these energy threads seeped into its muscles, that section of its body visibly strengthened. This was the effect of the specially formulated aptitude-boosting medicine Aoki had prepared based on his system's calculations.
Aoki watched intently, not wanting to miss a single detail. This was the first official trial of the aptitude potion, and its effectiveness on Marshtomp would determine how he used it on his other Pokémon in the future.
The system, now fully active, monitored Marshtomp's physical condition in real time. The readings surged rapidly, breaking past its previous limits—clear evidence of evolution's transformative power. Evolution was a fundamental leap in a Pokémon's capabilities. Even a Pokémon with average potential would see significant improvements in physical strength and energy control after evolving.
"Soon," Aoki murmured.
"Gaaah—!!!"
With a sudden cry, the Marshtomp's glowing form solidified, the white light of evolution fading away. As soon as the light dissipated, the Pokémon slumped to the ground, exhausted.
Aoki immediately placed his hands on Marshtomp, letting the system scan its condition to assess whether the aptitude potion had worked as intended.
Pokémon: Marshtomp (Cyan)
Gender: Male
Level: 16
Type: Water / Ground
Ability: Torrent
Held Item: None
Egg Moves: Ancient Power, Bite, Mud Bomb, Refresh
Basic Moves: Mud Shot, Tackle, Growl, Water Gun, Mud-Slap, Foresight
Taught Moves: Water Pulse, Aqua Tail, Icy Wind (Taught by Weavile)
TM Moves: None
Marshtomp's potential had risen from light cyan to full cyan—a significant improvement. Additionally, while it had been purely Water-type before, its evolution granted it the dual typing of Water and Ground. This new attribute combination meant it now only took quadruple damage from Grass-type moves, while resisting Poison, Rock, Steel, and Fire-type attacks. Most importantly, it was now completely immune to Electric-type moves, a major weakness for most Water-types.
For Aoki's planned rain team, this typing was invaluable. Even before considering Mega Evolution, Marshtomp's natural resistances made it a sturdy combatant.
Gently patting Marshtomp's head—the texture reminding him of a Slowpoke—Aoki smiled. "Congratulations on evolving. Now, let's push your limits even further."
"Gaaah!" Marshtomp responded enthusiastically before slumping again, still fatigued from the evolution process.
The aptitude potion had succeeded in boosting its potential, but the strain of evolution had left it weakened. Still, this was a minor side effect—a few days of rest would fully restore it. Compared to the benefits, the drawback was negligible.
Seeing Marshtomp's successful evolution and aptitude improvement, Aoki felt the investment in the potion had been well worth it.
"Take it easy for the next two days," Aoki said, ruffling Marshtomp's head again. "Consider it a reward for being the first to evolve."
The other Pokémon quickly gathered around, congratulating their teammate. Honchkrow and the more experienced Pokémon offered brief praise before returning to training—evolution was nothing new to them. The younger ones, however, poked and prodded at Marshtomp with awe, fascinated by its transformation.
Aoki felt a slight shift in weight as the two Swablu on his shoulders fluttered down to join the others. Though they had been raised comfortably under Altaria's care, they had recently grown curious about battling after watching Marshtomp, Larvitar, and Aron train.
Aoki didn't interfere. Altaria was watching, and he had promised not to restrict their freedom. Besides, he wasn't about to challenge Altaria's authority—that was a battle he wouldn't win.
With the month's training nearly complete, Aoki decided it was time to leave the gym and test his team in real battles. Staying cooped up only benefited Marshtomp and Poliwag—Torchic, in particular, needed more experience to grow.
At level 14, Torchic was close to evolution. Its aptitude was dark blue, and Aoki wondered if the high-grade aptitude potion could push it even further. That would be even more crucial than Marshtomp's evolution.