Sofia Sakharov is a Russian seventh grader at Aibo Academy who outwardly serves as the composed vice president of the middle school student council while secretly acting as a Disaster agent. Reporting directly to Kyoya Gaen, her primary missions involve identifying potential recruits and distributing Dark Cores to manipulate fighters. She maintains a calm, serious demeanor with intense loyalty, rarely showing emotion except malice or annoyance when provoked or when her strategies collapse. Her dedication drives her to execute Kyoya’s orders unquestioningly, including erasing memories of former allies like Terumi Kuchinawa. In season one, Sofia assists Magoroku Shido in overseeing the ABC Cup and later competes in the Gaen Cup under Team Purgatory. She wields a Legend World deck focused on the 《Star》 attribute, using "Stellar Deity, Astraeus" as her Buddy alongside the Set Spell "Great Fate, Frozen Stars" to lock opponents by nullifying their card abilities while Astraeus shields her 《Star》 monsters. Draw effects from cards like "Symbel Gard" and "Rigel Orion" gather combo pieces, while defensive spells such as "Holy Grail" protect her center. Overconfidence leads to her pivotal defeat against Tetsuya Kurodake, where psychological tactics break her composure and cause Disaster’s first tournament loss. She later triggers a portal generator’s self-destruct to cover her escape after Kyoya’s defeat. During season two, Sofia adopts the alias "Death Shido" under Ikazuchi’s command to hunt Omni Lords, initially using a Legend World deck with Twin-Headed Hellhound, Orthrus as her Buddy. This deck employs destructive tactics like Orthrus’s monster-destruction ability and "Decree of Dullahan" for double attacks. She later switches to a Danger World deck and ultimately a Star Dragon World deck featuring "INV Sixth Omni Storm Lord, Catastrophe Cord" as her Buddy, focusing on rapid gauge accumulation to fuel Crossnize effects and sustain Soulguard defenses. Though her loyalty shifts to Ikazuchi, it remains anchored in Kyoya’s overarching plans. She demonstrates pragmatic cruelty by deflecting Ikazuchi’s punishments onto Shido using shields during failures. Sofia undertakes a mission with Tasuku Ryuenji to investigate Star Dragon World’s future, discovering a post-apocalyptic Earth where they encounter children resembling themselves. She expends her Disaster Force to awaken the Eighth Omni Lord, leaving her weakened. In the final conflict against Yamigedo, she is corrupted by his spirit after allowing Tasuku passage, resulting in petrification. Rescued by Variable Cord using Disaster Force, she unseals Inverse Omni Lords for Kyoya and aids combat against the Hundred Demons with Photon Saber, Meteor. She delivers the Inverse Omni Lords to Kyoya for his deity ascension plan, evacuating him when Yamigedo retaliates. Her abilities include Disaster Force, which alters her appearance with serpentine eyes and elongated hair, enabling teleportation, energy projection, and unconsciousness induction. She possesses impersonation skills, notably as Death Shido, and strategic deck adaptation across Legend, Danger, and Star Dragon Worlds to suit evolving objectives.