Alva stands as the primary antagonist. As the Mega Evolution Councillor of the Azoth Kingdom, he wields his authority to pursue a personal ambition: seizing power through the unique capabilities of Magearna. His personality displays pronounced sadism and megalomania, showing minimal regard for humans or Pokémon. He spent years manipulating Prince Raleigh, molding the prince's loyalty solely for his own objectives.

Alva orchestrated the theft of Magearna's core component, the "Soul-Heart," intending to harness its immense power as an energy source. His goal was transforming Azoth Castle into a weaponized flying fortress under his command. To achieve this, he utilized "arcane science" and a technology called "Mega Wave," forcibly inducing Mega Evolution in Pokémon under his control. This process inflicted significant distress and pain on the affected Pokémon. His methods included psychological and physical coercion; he tortured Magearna by electrocuting its companions, including Ash and his friends' Pokémon, to break its spirit and ensure compliance. He recruited Team Rocket for assistance, only to abandon them callously once their usefulness ended.

Upon facing defeat, Alva revealed his cowardice and spitefulness. He programmed the flying fortress to crash into Nebel Plateau, aiming to destroy his adversaries, Volcanion, and Magearna's allies while attempting a solo escape using a jetpack. Princess Kimia apprehended him after the fortress's destruction. Resisting surrender and trying to flee during his arrest, he became ensnared by his own magnetic bands on Kimia's aircraft. This led to his ultimate capture alongside his subordinates, Levi and Cherie. His primary Pokémon is a Shiny Gengar, which he forcibly Mega Evolved using his arcane science techniques.