Shiro was originally a pilot for the Galaxy Garrison, an organization dedicated to studying outer space. One day, on a trip to Pluto's moon Kerberos with Dr. Samuel Holt and his son Matt, the three were abducted by the Galra, an alien species of conquerors bent on taking over everything. While in Galra captivity, Shiro was sent to fight as a gladiator, and defeated everyone he was forced to fight. This led to Shiro being experimented on by the witch Haggar, the personal attendant of the Galra's leader Zarkon. After Shiro was genetically enhanced and granted a cybernetic right arm, a Galra rebel named Ulaz helped Shiro escape from the Galra and flee back to Earth. After crashing on Earth, Shiro was taken into custody by the Garrison and freed from them by Keith, Lance, Hunk, and Pidge, four teenagers who witnessed his crash. The five soon came across the Blue Lion, a piece of the superweapon Voltron that the Galra were searching for, and it took them to the planet Arus. They then accidentally freed an alien princess named Allura, along with her assistant Coran, from cryogenic hibernation. Once Allura saw that they had the Blue Lion, she decided that these five were meant to use Voltron to defeat the Galra Empire once and for all. Shiro was made the pilot of the Black Lion, the head of Voltron, making him the leader of the five Paladins.
Skilled Pilot: Shiro is a skilled pilot with a legendary reputation as one of the best on Earth. Out of all of Voltron's Paladins, Shiro is easily the best of them in terms of piloting his Lion.
Skilled Hand-to-Hand Fighter: Due to being stuck as a gladiator for a year, Shiro is incredibly skilled in hand-to-hand combat. He can easily take on Galra soldiers with his bare hands, and even match Sendak, Zarkon's second-in-command, in a fight.
Bond with the Black Lion: Shiro's bond with his Lion is the best of all the Paladins, and is even superior to the Black Lion's bond with its original Paladin, Zarkon. This allows Shiro to see through his Lion's eyes and get visions of the Black Lion's memories.
Cybernetic Arm: While in Galra custody, Shiro's right arm was removed and replaced with a robotic prosthetic. This robotic arm is much stronger than Shiro's regular arm, and can emit energy that Shiro can use like a blade to slice through solid metal with ease. As a piece of Galra technology, Shiro can use the arm to interface with and activate other forms of Galra tech.
Paladin Armor: The standard armor worn by Paladins of Voltron. The armor protects Shiro from harm, allows communication with the other Paladins, and is equipped with a jetpack for sustained flight, along with an energy shield to block attacks. The helmet produces oxygen when worn, allowing Shiro to function normally underwater or in a vacuum, and the bracers can fire small lasers or project holograms of Shiro.
Bayard: The Bayards are the Paladins' main weapons when on foot. Each one takes the form most well-suited for its Paladin. However, Shiro has never used his Bayard in combat, with it being in Zarkon's possession for most of the series, though Shiro did manage to retrieve it. When Zarkon used it, it could take multiple forms, such as a cannon, a broadsword, a whip-sword, or an energy shield, though its unlikely Shiro could make it take these forms as well.
The Black Lion: Forged from a meteor that crashed on the Galra homeworld, the Black Lion is one of the five robotic lions that combine together to form Voltron. When the five lions form Voltron, the Black Lion forms into the head and torso of the giant robot, and Shiro, as its Paladin, is the leader of the Paladins as a result. The Black Lion is the strongest of the Lions, able to destroy an entire fleet of Galra ships by itself, and is extremely balanced in terms of strength, speed, and durability. All the Lions are sentient to some extent, and can move to protect their Paladins without a pilot.
Armor: The Black Lion's armor is incredibly tough, able to take laser blasts and explosions without a scratch.
Rocket Boosters: All the Lions have rocket boosters mounted on the back, allowing for high-speed flight. The Lions are each fast enough to travel from Earth to Pluto in seconds, making them faster than the speed of light.
Laser Cannons: The Black Lion has laser cannons stored inside the mouth and tail, both of which have enough power to pierce through a Galra ship in one shot.
Jaw Blades: For close-ranged combat, the Black Lion can form blades from its jaws that can slice clean through a Galra ship. The jaw blades can also be thrown like a boomerang.
Wings: Unlike the other Lions, the Black Lion has a pair of wings on its back. While they normally appear simple, Shiro can unfurl the wings, making them larger and covered with bladed energy feathers that can destroy several ships with one strike. Unfurling the wings also grants the Black Lion a massive boost in speed and power, along with the ability to phase through solid objects.
In the original Voltron show, Shiro was named Sven Holgersson, the Norwegian former pilot of the Blue Lion. When Voltron: Legendary Defender was made, the creators changed his name and ethnicity to that of his GoLion counterpart, Takashi Shirogane, and made him the Black Lion's pilot to match the black coloring of his uniform.
There have been discrepancies regarding Shiro's age. When asked about ages at San Diego Comic Con 2016, Tim Hedrick, Joaquim Dos Santos, and Lauren Montgomery agreed on the "safety zone" age of "25" for Shiro. However, the DreamWorks website and published Comic synopses describe the group of Paladins as "five unsuspecting teenagers", making him no older than 19.