As a trainer of the Viridian Forest, Lance has the ability to hear the thoughts of Pokémon, and can heal their injuries. However, Lance also possesses an additional ability to control any Dragon-type Pokémon. This ability also extends to Pokémon with similar attributes to Dragon-type Pokémon, namely Aerodactyl and Tyranitar.
Lance makes his first appearance at the Vermilion City, where he observes the Vermilion City Surfing Competition, which Yellow participates in. He abruptly intervenes, proclaiming that the Dragonair put forth as the prize belonged to him. Lance then proceeds to decimate the entire town, desperately searching for something. When Yellow tries to stop Lance from leaving, he proclaims that he might as well capture Pika, considering that Agatha and Lorelei failed to do so. However, Lance is surprised when Pika uses his HP as a funnel, allowing Yellow to travel across the water's surface. He is subsequently electrocuted by Thundershock, and he cedes into a retreat.
Later, Lance appears before Yellow and Blaine at Cerise Island. He finds himself fighting against Blaine's trump card, Mewtwo, who is able to hold its own against Lance's Dragon Pokémon. However, due to Blaine's ailing condition, Lance is able to prevail over Mewtwo, as both combatants collapse. As a last resort, Blaine attempts to destroy Lance's Poké Ball to prevent him from summoning more, but Lance reveals that he released them long ago to combat this possibility. With Yellow and Lance being evenly matched, Lance takes the battle high up above the Cerise Island skyline. With the newfound advantage over Yellow, Lance uses his Gyarados and Aerodactyl to generate a multitude of bubbles, which Yellow cannot detect in the blinding sunlight.
Just when it seems that Yellow will be defeated by Lance, Giovanni intervenes in the battle. He proceeded to use his Rhyhorn to kick up a sandstorm, making Lance's bubbles visible. However, Lance factored Giovanni's intervention in his plan, as the Earth Badge is forcibly taken from his jacket pocket. Lance proceeds to use the final Gym Badge to complete the Energy Amplification Device, summoning Lugia. However, even with the assistance of Lugia, Lance was defeated by a combination of Yellow's recently evolved Pokémon, who channeled their power into Pika's Megavolt. After being defeated, Lance wished to find out who Lugia's real master was, as he was unable to control it.
Lance went into hiding in the Johto region, working fervently to find out more about Lugia. He first appears before Silver, whereupon he imparts advice on how to defeat Team Rocket. Lance also gave Silver his Tyranitar, which was subsequently returned after he was defeated by the Mask of Ice at the Lake of Rage. Lance briefly assisted Silver and the other Pokédex Holders in the battle against the Mask of Ice, and after this was achieved, he leaves on his Aerodactyl.
Aerodactyl is primarily used by Lance as a form of transport, as he is frequently using it to travel. It is also potent at battling, as shown during the conflict with Yellow. His Aerodactyl's wings are sharper than swords. Aerodactyl's Moves: Hyper Beam, Wing Attack, Supersonic, Fly
Dragonite is Lance's powerhouse, and has been by his side since it was a Dratini in his childhood. It also possesses the ability Multiscale, which makes it impervious to high intensity attacks. Dragonite's Moves: Hyper Beam
Dragonair was initially seen at Vermilion Harbor, where Lance used it singlehandedly to destroy the Vermilion City. Two additional Dragonair were seen at the battle at Cerise Island, shielding Lance from the erupting lava. Dragonair's Moves: Whirpool, Surf, Hyper Beam, Slam, Wrap, Agility.
Lance leant Silver his Tyranitar during the Gold, Silver and Crystal Chapter, in order to deal with Team Rocket resurfacing in Johto. It was strong enough to decimate Gold's team, but was taken off-guard by Togebo's Double Edge attack. Despite its strength, Silver is unable to control Tyranitar. Tyranitar's Moves: Sandstorm.