Subaru Okiya serves as the alias for Shuichi Akai, an FBI agent who faked his death with assistance from Shinichi Kudo's parents. Presenting himself as a quiet doctoral engineering student at Tōhō University, he resides at Shinichi Kudo's house after his apartment's destruction. His demeanor remains reserved and unflappable, maintaining composure during high-stress confrontations or hostage situations. He exhibits polite, friendly behavior toward children like the Detective Boys, attentively listening to their case theories, and enjoys cooking. This alias was meticulously crafted: "Subaru Okiya" draws linguistically from Char Aznable's real name, Casval Rem Deikun, in the Mobile Suit Gundam series. He is left-handed and drives a red Subaru 360 vehicle, reinforcing his cover identity. In "The Scarlet Bullet," Subaru Okiya operates critically after receiving FBI intelligence linking recent World Sports Games sponsor kidnappings to parallel Boston crimes 15 years prior. He coordinates with Conan Edogawa, analyzing patterns to predict an automobile CEO as the next target. When CEO John Voit is abducted during Tokyo's WSG, Subaru pursues the culprit using a GPS tracker Conan placed on Voit. The chase leads to an abandoned warehouse, where Masumi Sera and Mary Sera attack him, grazing his disguise mask. Undeterred, he continues the pursuit. Recognizing the full threat of the culprit's plan, he later discards the disguise entirely, resuming his identity as Shuichi Akai to intervene in the crisis aboard the high-speed "Hyper Linear" train.