Sheith

Sheith is a slash ship between Takashi Shirogane and Keith in the Voltron: Legendary Defender series.

Canon
Before Keith and Shiro became the Red and Black Paladins, they met at an undetermined point in the Galaxy Garrison, an institution for training astroexplorers, and Shiro acted as Keith's "guiding light". While exactly what transpired is unknown, Keith has frequently stated in the show that it deeply affected him, even saying in the premiere for Season 3, episode 1, that, "Shiro was the only one that didn't give up on me––I won't give up on him." Keith was expelled from the Garrison after Shiro went missing during a mission and space, presumed dead due to his own piloting error.

It has been confirmed in canon that Shiro is one of the most important people in Keith's life. In the Blade of Marmora, Keith's suit allowed him to hallucinate his greatest hopes and fears. In the first hallucination, Shiro appears as Keith's greatest hope, with the hallucination-induced Shiro subsequently abandoning him as his greatest fear.

Shiro and Keith have engaged in a lot of casual and comforting touches over the course of the four seasons, including, but not limited to: shoulder touches, clasped hands, and emotional hugs. This is exclusive to their dynamic, and they are not shown to exhibit this kind of bone-deep familiarity with any of the other characters on the show.

Likewise, they are very comfortable with each other, to the point where many fans of the ship have speculated about the exact nature of their relationship pre-Kerberos, and Keith is the only person Shiro allows himself to be truly vulnerable around.

Fanon
Along with Klance, the ship has really taken off for modern audiences in the last couple years. This is thanks to Voltron: Legendary Defender Season 2, produced by Studio Mir (Legend of Korra). A lot of the writers and directors for Voltron migrated from Korra, famed for it's bisexual ending, and have made comments hinting at possible LGBT content, including the quote, "I think I'll just let that play out as we go. No comment on that question," when prompted about future LGBT content. Although the ship is not confirmed in canon, many fans still enjoy Keith and Shiro's dynamic in a fanon environment due to the deep connection Keith and Shiro have been shown to share over the last four seasons.

The ship has received hate because of its prospective age gap. Many contradicting age ranges have been mentioned by many different official sources, some fans consider that there are no definitive set ages for Keith or Shiro, or for any of the other Paladins, while others do not consider any published age information canon.

Keith's published age is 18 by The Paladin's Handbook official guidebook, while Shiro's published age is 25. Shiro's age contradicts the official series synopsis published as "Five unsuspecting teenagers transported from Earth", and Keith's age contradicts executive staff verbally agreeing that the Paladins, sans Shiro, are "not adults". The book is suggested to take information from the show "bible" or "original pitch", but series staff Joaquim Dos Santos and Lauren Montgomery have expressed concerns that their ideas have changed organically over time, so information may not be accurate, and they did not review the book for errors before publishing.

The ship has been acknowledged by countless members of Voltron's production team since the show first aired, further supporting it as a ship for fans to enjoy. These instances include:
 * Members of the production team such as art director Chris Palmer, Steve Ahn, Christie Tseng, Barlee, and Lauren Montgomery liking Sheith fanart on various social media platforms.


 * Voice Actors such as Bex Taylor-Klaus and Josh Keaton mentioning the ship on several occasions on social media, including when Keaton suggested the ship name "sheith", and the instance wherein Taylor-Klaus declared that Keith is a powerbottom in response to Keaton posting a picture of red and black shoes.


 * Members on the staff such as former art director Chris Palmer and Kim Il Kwang produced art that emphasizes the bond between Shiro and Keith, and are often theorized to have romantic undertones.

Quotes
These are quotes that are commonly considered "Sheith quotes" aka quotes that are usually associated with the romantic pairing of Shiro/Keith
 * "At this moment, your friend desperately wants to see you." - Kolivan, Blade of Marmora
 * "Keith: It's good to have you back. Shiro: It's good to be back." -The Rise of Voltron.
 * "If it wasn’t for you, my life would have been a lot different.” - Keith, Across the Universe
 * "Shiro is the only person who didn’t give up on me - I won't give up on him." Keith, Changing of the Guard
 * "Shiro: It's good to have you back. Keith: It's good to be back." - The Ark of Taujeer
 * "Shiro: How many times are you gonna have to save me before this is over? Keith: As many times as it takes." – Taking Flight
 * "It's killing me when you're away." - Keith

Trivia

 * Keith pilots the Red Lion, which forms the right-hand of Voltron, thus making him the right-hand man of Shiro, who lost his right arm to the Galra.
 * Keith is part Galra, and Shiro's right hand was replaced by a Galran prosthetic.
 * The ship name was coined by Shiro's voice actor, Josh Keaton, after he proposed "Sheith" on his Tumblr blog.
 * Shiro's Bayard, when combined with Keith's, activates Voltron's Blazing Sword, and it's a joke within the community that Shiro lights Keith's fire.
 * In an AfterBuzz interview, it was brought up that the fans discovered Keith and Shiro in the background flashback with Matt and Pidge. Lauren and Joaquim contraguated the fans on a well done for finding the easter egg. Lauren commented with "I put that shit in there. Oh, I just said a bad word." and "Shiro was still his guiding light, it was good."