Childhood Friends

There are many kinds of friendship. Work friends, friends from your class, drinking buddies and more. Yet one of the very closest types of friendships is that of the Childhood Friends. Before you have to worry about the shock of betrayal or the possibility of romance, this is the friend that will have your back. No one knows you better than these friends. And it shows when childhood friends are treated more intimately or are trusted more than other friends.

This is a supertrope of Childhood Friend Romance, Patient Childhood Love Interest, Beleaguered Childhood Friend, Forgotten First Meeting and Forgotten Friend, New Foe. Please do not add examples to this page that would fit better on one of those instead. Also contrast Old Flame Fizzle.

Anime & Manga

 * Nagi, Sakuya, Wataru and Isumi are all childhood friends in Hayate the Combat Butler. While Wataru does like Isumi, for the most part it's entirely platonic. A large portion of the cast dynamics revolves around their relationships together. And surrounding them is their families and how they interact. In fact, they seem to be Generation Xeroxes to an extent, though their parents are very minor characters.
 * Reinhard von Lohengramm and Siegfried Kircheis in Legend of the Galactic Heroes had a bromance as epic as the title of the show. Their shared childhood memories were commonly shown in flashbacks.
 * Lelouch and Suzaku in Code Geass. Basically the only reason why Lelouch didn't brainwash or kill him early on.
 * At some point, Lelouch says, "You're the only one I didn't want to use the geass on," referring to Suzaku, and the reason he did it was to force Suzaku to save himself, other than that one time Lelouch doesn't care who he brainwashes (including his own sister, who is supposedly the reason he's trying to change the world), Childhood Friend Romance maybe?
 * Quite a few among the Shinigami in Bleach, including Rukia and Renji, Hitsugaya and Momo and Gin and Rangiku. While fans occasionally have shipping lines along these angles, there's nothing confirmed or beyond the level of an occasional hint. During the soul society arc, these interactions led to a level of conflict among lieutenants and captains that was throwing the entire area into turmoil.
 * SUBVERTED with Ichigo and Tatsuki. Despite being childhood friends, the above traits do not apply to their bond. However, they're shown to still care about one another despite their new distance; it shows in moments such as Tatsuki being offended and hurt when Ichigo refused to trust her with important information (for her protection), punching him through a wall and asking "aren't we nakama?!". They simply grew apart as they got older, but definitely maintain some closeness (though not to the point that a Childhood Friend Romance seems likely). It helps that they have a mutual friend in Orihime.
 * Kyouko and Sho in Skip Beat were friends in childhood, and know each other just as one would expect with all those years of experience....although calling them "friends" currently would be something of a mistake.

Literature

 * One of Larry's regrets in The Stand was how he ruined a childhood friendship by quibbling over a small amount of money when he knew perfectly well he was wrong. It's one of the memories he holds to convince himself that he 'aint no nice guy.' We never see his friend in the present (he probably died in the superflu pandemic), but it clearly bothers Larry at how pointlessly selfish he was and how he lost a really good friend over it.
 * Derek and Laura of the web-novel Domina. She moved away years ago for reasons he doesn't understand--all she'll say is that its his fault.
 * Cassel and Lila from White Cat by Holly Black.

Video Games

 * Kouin, Yuuto, Kaori and Kyouko of Eien no Aselia fall into this. Kaori doesn't have much of the dynamic, and Kyouko is more of a romance, but Kouin and Yuuto definitely fall into this.
 * Yuuki and Heita in Big Bang Age. Yuuki is apparently one of Heita's only real friends and the two are rather close. He's rather... surprised to learn the truth about Yuuki, too. Both are rather minor characters, though, so the relationship isn't as fleshed out as it could be.
 * In the mage starter area in Dragon Age Origins, the player character and Jowan are quickly established as having been close friends since the age of five or six -- this is probably a deliberate attempt to make the player more inclined to go along with Jowan's (illegal, and questionably moral) plans and/or care about his fate later in the game. There even seems to be a possible dialogue option to defend why you placed your trust in him that is something to the effect of, "but we've been friends since we were kids".
 * Alex and Kyle from The Colour Tuesday. Its the bedrock of their alliance.
 * Phoenix Wright, Miles Edgeworth, and Larry Butz from Ace Attorney.
 * Shulk and Reyn, from Xenoblade.
 * Aden and Sonja, the protagonists of Rune Factory: Tides of Destiny, have been friends since birth.
 * Endou and Kazemaru in Inazuma Eleven, but it's never been disclosed how long exactly.
 * In GO, Tenma and Aoi. According to the latter's seiyuu Aoi has a crush on Tenma, but it has yet to be seen or hinted at.
 * From GO as well, Amagi with Mahoro and Yukie. That is, before they fell apart when Mahoro started actively avoiding Amagi.
 * Garlot, Siskier, and Jenon in Blaze Union. Both Siskier and Jenon have got some sticky feelings that complicate things, but for most of the game the three are nigh inseparable and their almost-familial friendship is an important source of emotional support for Garlot.
 * Ceodore and Ursula from Final Fantasy IV: The After Years. Despite they reveal they are childhood friends, they seems only share only one scene together in the whole game. You do get to use their powerful Combination Attack, though.

Visual Novels
"Kouichi: Say... Ichimonji-san, do you have someone you can call a childhood friend?
 * Arihiko and Shiki in Tsukihime. Arihiko is one of the few people who really knows all about Shiki and understands him and the two are mostly inseparable.
 * Shiki and the maids. Also, Akiha except she is his sister even though she's not really his sister.
 * Yoshiyuki, Wataru and Koko are all childhood friends in Da Capo II. Koko's relationship with the other two gets much more complicated, but Wataru and Yoshiyuki fall straight into this intead. It's one of the factors that makes Koko's route that much more dramatic.
 * In Tokimeki Memorial 2 Substories: Leaping School Festival, an Event in Homura Akai's route reveals that  are childhood friends, and still are the best friends in the world despite.
 * And then there's Homura herself with Akane Ichimonji. The two are best friends since childhood, although Akane feels from time to time the need to take a break from Homura and avoids her, as shown in an Event in Childhood Mode. Speaking of Akane, in the 10th Drama CD, she and the protagonist, Kouichi, discuss about childhood friends:

Akane: Me? Mmm... Well, someone I could call as such... I'd say Homura.

Kouichi: Aah, Akai-san, huh?

Akane: Well, rather than a childhood friend, she's more like a kusare-en (= a destined friend, a fatal bond) to me.

Kouichi: I see.

Akane: But, it's nice to have childhood friends.

Kouichi: Is that so?

Akane: They know each other very well, and can say everything to each other! They're like best friends, or even family!

Kouichi: Family... huh...

Akane: If you look around it, Homura too has a nice side.

Kouichi: I know that.

Akane: Everyone are saying lot of things, but I love Homura!"


 * The original eponymous Little Busters were made up of five childhood friends, four guys and one girl.
 * Hiroki and Yanagi in Canvas 2.
 * In Maji De Watashi Ni Koi Shinasai we have both the Kazama Family including seven people, and the 2-S trio of Touma, Jun, and Koyuki.

Webcomics

 * Penny, Sara and Michelle of Penny and Aggie have been friends since their preteen years, Penny and Sara for at least two years longer. Word of God also has it that Fred and Daphne have been best friends since childhood.
 * Lee and Frank in Prince of Cats met in, and have inseparable since, second grade.