Lightspeed Flash, alias Flashy Flash, serves as Rank 13 among the Heroes Association's S-Class heroes. A graduate of the Ninja Village's 44th class alongside Speed-o'-Sound Sonic, he annihilated the entire village during graduation exams – instructors, officials, and classmates – for undisclosed reasons, cementing his legend as a lethally skilled ninja. His physique is lean and agile, perfectly suited for speed-based combat. He wears a form-fitting dark hero costume reflecting his ninja origins, prioritizing minimalism for maximum mobility at high velocity. He brandishes a specialized weapon named Instakill. Flash's defining power is extreme superhuman speed. This enables feats like generating afterimages, traversing water and vertical surfaces, and executing limited aerial maneuvers. His combat speed allows simultaneous engagement against multiple high-level threats, demonstrated by defeating Dragon-level monsters Gale Wind and Hellfire Flame without fatigue, and later confronting Platinum Sperm and Pre-Awakening Garou – opponents capable of overwhelming other S-Class heroes. Narrative claims describe his speed as "faster than light," though measurable feats suggest lower velocities; this discrepancy remains unresolved. He combines raw speed with exceptional technical mastery, proficient in multiple unarmed and weapon-based techniques, particularly with Instakill. His attack potency threatens Small Country-scale entities, amplified by his blade. Durability matches this tier, enduring strikes from Platinum Sperm (whose weaker form knocked out Superalloy Darkshine) and surviving Garou's Monster Calamity God Slayer Fist. Superhuman stamina sustains prolonged engagements against multiple Dragon-level opponents. Personality-wise, overconfidence fuels impulsive attacks on unidentified individuals regardless of allegiance, occasionally compromising tactics. Pride in his speed makes him vulnerable to psychological destabilization if outraced, potentially impairing effectiveness. Despite these flaws, he maintains professional commitment to hero duties, frequently confronting catastrophic threats alongside fellow S-Class heroes. Key developments include his conflict with Speed-o'-Sound Sonic. Sonic's post-defeat training and Monster Cell consumption pressured Flash into using two Ultimate Techniques, highlighting Flash's capacity for growth through adversity, though he prevailed. Battles against Garou during the latter's monsterization further tested his limits; Garou eventually surpassed him in speed after initial exchanges.