Description
Lain Valhalla (known as Lean Walhalla in Japanese releases) stands tall with pale skin and spiked magenta hair featuring light pink highlights that shift cyan when his power intensifies. His yellow eyes contain dual thin rings per iris, unique among characters, complemented by magenta facial markings that glow during Beyblade resonance. He typically wears a dark-blue sweatshirt with light blue markings and mint green fur collar, indigo pants, red boots with mint green collars, violet belts with red buckles on limbs and torso, and a dark-red fingerless glove on his left hand. A black coat with violet buttons adorns him outside battles.

Originally a solo rookie Blader, Lain wielded "Flare"—a dark resonance power growing with each victory or loss against worthy opponents. He forged the first Superking Beyblade, Origin Uranus Mobius 2D, dominating New York tournaments by bursting all challengers. Shu Kurenai recruited him for the Raging Bulls to control his Flare and teach Beyblade's enjoyment. Shu's training emphasized strategy, balance, and analytical skills, including tightrope launches. Despite mastering these, Lain's Flare and aggression escalated. After defeating Free De La Hoya, dissatisfaction drove him to evolve his Beyblade into Vex Lucius Mobius 2D, rejecting Shu's guidance and vowing to end legendary Bladers' careers.

His personality merges calm aloofness outside combat with extreme battle aggression fueled by an "unstoppable dangerous Flare." He dismisses Bladers unable to match his power, threatens legends like Lui Shirosagi and Valt Aoi, and roars to assert dominance. Post-victory, he loses interest in opponents, exemplified by ignoring Hikaru Hizashi mid-tag battle. Defeats trigger violent rage and retaliation threats, as seen after losses to Shu or Lia Tanikawa. His sole soft spot is his pet hedgehog, Harry, whom he gently pets between battles. Harry mirrors Lain's aggression, hissing at those he dislikes, like Valt Aoi or Hyuga Hizashi.

Beyblade evolution tracks his power pursuit:
- **Origin Uranus Mobius 2D**: Lightning Beyblade enabling early dominance.
- **Vex Lucius Mobius 2D**: Evolved post-Free victory, featuring barrier-warrior mechanics and moves like *Vexing Wall* (defensive barrier) and *Vexing Crush* (stadium-shattering pincer attack).
- **Lucius Endbringer Kou Drift**: Post-Shu defeat Limit Breaker Beyblade with a free-spinning ring to repel attacks and activate destabilizing *Vexing Disaster*. Fanon continuities introduce evolutions like *Fallen Luxnoct Drop Bearing Mobius-13* and *Barricade Luxnoct Illegal Bearing Drift-14*.

Development unfolds through conflict. After losing to Shu, he evolves Lucius but destroys the stadium in rage. During the Ultimate Tag Series, pairing with Shu against Valt and Rantaro ignites a "Friendship Flare" resonance with their style. A semi-final loss to Hikaru and Hyuga Hizashi cements his embrace of Beyblade's communal spirit, forging friendly rivalries and abandoning his quest to end legends' careers.

Key relationships steer his path:
- **Shu Kurenai**: Mentor turned rival whose initial control efforts fail but later enable Lain's redemption in tag battles.
- **Hikaru and Hyuga Hizashi**: Initially dismissed (even their Beyblades destroyed), later earning mutual respect and rivalry post-defeat.
- **Uzuki Tennoji**: Fanon depicts them as accomplices inventing the Superheavy Layer System.
- **Lia Tanikawa**: Her repeated victories over Lain fuel his fanon evolution to Luxnoct Termination.

Notable quotes include battle challenges like "TAKE ON MY FLARE!" or "DIE!" to Valt Aoi, and philosophy: "Strategy and tactics are vital to battling." Trivia notes his A-Tier rank (#1, globally #16), Scandinavian descent, and status as Burst's third pet-owning character.