In fantasy based fictions, it is a recurring feature that weaker heroes would enter into a contract with a stronger being for protection or any other deal. But wait! What if they are required to enter into a contract using a kiss? Then that's this trope: A Magic Contract Comes With A Kiss. This is a sister trope to Magic Contract Romance.
Note: Whilst Magic Contract Romance is only when a romance is ensued between the contractee and the contractor, this trope is the kiss that initiates the contract. Know the difference.
This is a subtrope of Magic Kiss. Not to be confused with Signed with a Kiss, where a character kisses an object meant for another person.
- The Elder Sister-like One has the beautiful but inhuman demon Shub-Niggurath bargaining with the male protagonist to become his sister. She seals the deal with a particularly aggressive and wet kiss.
- In Fairy Ranmaru, the titular fairies need to kiss the Woobie of the Week in order to transform into their battle forms and exorcise the wicked soul that is making the victim's life impossible. While kissing their hands seems to work just fine, they usually go for the lips.
- In Kamisama Kiss the contract between a god and a familiar is sealed with a kiss. Small surprise since it is a shojo manga.
- Invoked in Majo no Shinzou by Lumiere, when Mika contracts him to be her familiar. Much to Mika's consternation. He's lucky she's such a nice girl who doesn't want to hurt him, or else she'd have turned him into dragon steak.
- In Negima! Magister Negi Magi, because mages are generally vulnerable to attacks as they conjure their spells, they form 'Pactios' with a guardian they trust to protect them. The master is called the Magister Magi (Magistra Magi if female) and the servant a Minister Magi (Ministra Magi if female). The easiest way to form a 'Pactio' is through a kiss. Negi ends up making Provisional Pactios with about half of his class, although standard mage procedure is to select a single permanent Pactio partner later on - and it's stated that that is so because there's never been a mage with enough magical power to maintain more than one permanent Pactio bond (well, not yet anyway). It's pointed out that permanent Pactio partners very often end up getting married, so the contract generally carries a fair share of romantic subtext. It's also implied that there are other ways of forming a Pactio, but kissing is the most convenient way. The only alternative known is "open veins, swap blood", although the source of this being the only alternative is questionable.
- PandoraHearts: When Oz agrees to form a contract with the B-Rabbit Chain Alice, she immediately kisses him and takes over his body.
- Rozen Maiden has the contract starting with "Swear to me on this rose ring..." After kissing the ring, it vanishes from the doll, and appears in human scale on the finger of the newly made Medium. Undoing the contract is also possible by doing the process again but in reverse, i.e. the doll has to do the ring-kissing.
- Villainous version in Saint Seiya: The Lost Canvas. Upon finding Alone and recognizing him as the human avatar of King Hades, the mysterious Pandora marks him with a kiss, sealing his destiny.
- In Sekirei, this is the method used by Ashikabis to 'wing' Sekireis.
- In most versions of Steel Angel Kurumi, the Steel Angels are awakened/activated with a kiss, which causes them to immediately fall in love with the kisser and attach themselves to him/her as protectors. And stalkers.
- Tales of Wedding Rings: Sato receives the power of each of the ring princesses with a kiss. Of course, these are also explicit (albeit quick) marriage ceremonies, and the whole point of the Ring King is for the King to receive power from his bonds with his wives.
- The Greatest of Them All: Death solidifies Peter's status as her Champion by giving him a deep kiss. She implies that she didn't have to do it that way, but did so because it was amusing and to tick off Thanos, who was watching the whole thing (alongside others).
- In Onegai, Megami-Sama!, at the end of the first act, after Matagu's wish of Peorth becoming his girlfriend is approved, she seals it by kissing him.
- In Labyrinth, Jareth's tells Hoggle that he'll make him a prince if Sarah ever kisses him. When Hoggle expressed interest, Jareth's says "Prince of the Land of Stench". Later Sarah kisses Hoggle as thanks for saving her from the fireys and a slide opens up beneath them and they just manage to evade falling into the Bog Of Eternal Stench.
- A lot of fairy tales feature a magical contract being enacted because of a simple kiss. Where did you think the saying, "sealed with a kiss" came from in the first place?
- Amagi Brilliant Park: Royalty of magical worlds have this as their power. Seiya gets the power to read anyone's mind, with the limit of one use per person.
- Craft Sequence: In Two Serpents Rise, the contract merging Heartstone Holdings (owner of a substantial reservoir) with Red King Consolidated (a water company) is sealed and activated by a kiss between their two chief representatives: Malina Kekapania, and Kopil, the King in Red himself. There are zero romantic connotations, only one immense magical superstructure absorbing another.
Seventy-thousand-page contracts sitting in the RKC archives erupted with unearthly light. Blood signatures burned into reality; silver glyphs appeared on stone circles and obelisks throughout Dresediel Lex and in cities around the world, as if etched in an instant by giants with diamond chisels. The pacts built by hundreds of Craftsmen over thousands of billable hours were loose strands of rope, and the kiss one pull tightening them to a knot.
- Inverted in Date A Live. If Shido kisses a Spirit he seals their powers, which cause them to be hunted just for existing. Him, and his organization do end up protecting them and help them live in the world.
- In Doctrine of Labyrinths, when Felix puts the binding-by-forms on Mildmay, it's sealed with a kiss—which he doesn't warn Mildmay about first. When Mildmay reacts with shock, Felix just tells him he would probably prefer it to the alternative. It really doesn't help that Felix has a crush on Mildmay, which is frustrated by both Incompatible Orientation and the fact that they're brothers.
- In Jim Butcher's The Dresden Files, it is the kiss that seals the marriage bond — which has magical implications.
- Harry taking the position of Winter Knight is sealed by Mab having sex with him.
- The Familiar of Zero: It is standard procedure for a wizard to kiss their familar immediately after summoning them to seal the contract. Most of these familiars are non-human and so there is no romantic subtext. However, Louise is a void mage and they always summon human familiars, which leads to awkwardness when Saito appears in the summoning circle. Fridge Logic sets in when later, the settings' Pope is confirmed to be a void mage, and he has a male familiar. Since nobody really mentions any other way to seal the contract, this particular sealing kiss was probably laden with Ho Yay.
- When Diablo is first summoned in How Not to Summon a Demon Lord, Rem and Shera each kiss him on a cheek, which seems to be part of their failed enslaving ritual.
- A bleeding Rayfe in The Mark Of The Tala strikes a deal with his temporary captive, Andromeda allowing her to leave "if nothing happens" following their kiss. Andromeda concedes but receives a bite to the lip initiating a magicial tranformation within her via Blood Magic.
- Accepting a contract of this nature forms the climax of Pale's prologue chapter: Matthew, needing to retain Louise as a witness to a murder, but not wishing to see her harmed by the normal mechanics of The Masquerade, kisses her to lock away the memories of the event (until such time as they can send someone to take her statement). In the process, he takes on some of her debilitating health problems, the better to ensure that she survives to give her statement.
- Not quite a contract, but in The Scar, Silas uses this trope to activate the Magus Fin, a magical artifact implied to contain a powerful Gengris ancestor-spirit. And a peck on the cheek won't suffice; Silas has to tongue-kiss the little Gengris statue to entice it to aid him, which sometimes entails cutting his tongue on its razor-sharp ring of fangs.
- In The Testament of Sister New Devil, a Master/Servant contract is sealed by having the Servant kiss a magical symbol that appears on the Master. If the Servant chickens out and refuses to do it, he or she will suffer a curse until he or she relents.
- The Mystery Science Theater 3000 episode Soultaker: The titular angel of death (Played by Joe Estevez) tries to make the heroine join him in the afterlife, claiming she can do so with a kiss.
Mike: Oh, no, Joe's improving this!
- In Supernatural, this is how you make a deal with a demon. And no, it's not always with an attractive woman.
- Played straight in Season 2 when Dean delivers a swoon-worthy kiss upon the beautiful demon to which he is selling his soul.
- Parodied mercilessly when it's discovered that Bobby made a deal with Crowley, a demon who's been helping them. When Sam asks if they kissed, Bobby denies it, at which point Crowley clears his throat and shows the latest picture on his camera. Crowley in fact loves to seal a deal this way, especially if it's with a man who really doesn't want to.
Bobby: Why'd you have to take a picture!?
Crowley: Why'd you have to use tongue?
- When Azazel makes a deal with Mary, he kisses her while possessing the body of her dead father.
- In "The Monster At The End Of This Book", Lilith offers Sam a deal and won't settle for just a kiss.
- The Vocaloid song "Dream-eating Monochrome Baku" is about a Magical being who can eat bad dreams of people for a price. In the song he kisses the girl to seal the contract in the line "in that case let's make a promise with a kiss."
- Invoked briefly in Umineko: When They Cry, when Beatrice mentions that to borrow a demon's power, weak witches have to kiss… its butt, as a vow of submission. We never see it verified though (Beato probably invented the whole thing anyway).
- Lady of the Shard: The Phoenix kisses the Acolyte, marking her to receive her spirit in the event of her death.
- The Adventures of Jimmy Neutron, Boy Genius gives this a sci-fi twist: Jimmy makes a deal with an attractive alien warrior chick and is surprised when she suddenly tries to kiss him. Apparently that's her species' equivalent to shaking hands to seal an alliance.