In fantasy, it is a recurring feature that mages would summon a familiar, usually a demon or an owl. But wait! What if the being they entered a Magically-Binding Contract with is a humanoid or of their same species and at least one party develops romantic interest in the other? Then, this is a Magic Contract Romance. In many cases, the contract between the contractor and his/her contractee would also grant greater spiritual bonds between them, often furthering their relations with one another—often romantic feelings. In many cases, weaker heroes would also enter into a contract with a stronger being for protection.
A common plot regarding this trope would usually involve the breaking down of the contract—forcing the couple apart—in order to test the strength of the pair's love.
A subtrope of Rescue Romance and Magically-Binding Contract, the contractor and the being they summoned would generally admire the qualities of one another as they travel through a journey between life and death, until gradually they fall in love. If the contracted being was originally disgusted by the weakness of his/her contractor, then the contractor would usually gain affection of his/her contractee through bravery, his/her inner kindness, or other inner qualities. This trope is common in both anime and manga. When this trope is present, expect a lot of action. Why in the world would one summon a guardian unless in grave danger? Note, if the contractor is as powerful as his/her contractee or increased his/her power then this trope will usually lead to a Battle Couple situation.
- Chrono Crusade: Sister Rosette Christopher is contracted to Chrono. She gives him years off her life to return him to his true form and power. Because she means so much to him, he treats this like a Godzilla Threshold level resort.
- Coud and Ren in Elemental Gelade. Ren is an Edel Raid, a special type of human able to turn into a weapon when they form a contract with a Pledger. She chooses Coud to be her Pledger and they fall deeply in love.
- The Familiar of Zero has Saito contracted to Louise as her familiar and they later fall in love with one another.
Saito: Listen you! How long can I keep telling I love you to a girl who does not return my feelings?! I should be getting a medal for this!
- This trope has sinister underpinnings in the novels, where it's revealed the contract alters Saito's thoughts so he'll stay with Louise through suppressing his feelings about home as well as "conditioning" him into servility causing him to act fearless along with other compulsive behavior even though he's scared out of his wits and/or wouldn't have done them normally. Once the Mind Rape from the contract is undone he gets all the feelings of homesickness back in a large burst. As for the servility part he's trying to cope with that. They're dealing with both of these though Louise is making the first problem worse because she Cannot Spit It Out.
- Tomoki Sakurai and his Angeloids in Heaven's Lost Property.
- The main plot of Kamisama Kiss is Nanami falling in love with her familiar Tomoe, a Little Bit Beastly white haired Bishōnen Kitsune.
- 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. It is widely known that usually, the Magister/Magistra Magi usually contracts a Pactio with one of opposite sex and they end up marrying each other. Through the manga, this trope is most famously seen between Negi and his students. By the end of the series, Negi formed a pactio with two-thirds of his class!
- It should be noted that there is a great deal of evidence suggesting that forming a Permanent Pactio requires the Magister to have sex with the Ministra. This could explain the tendency of Magisters to marry their Ministras. Also of note, when Asuna first talks to Negi about forming a permanent pactio, he freaks out.
- This continues in the sequel UQ Holder!, with the main hero Touta making pactios with his female friends. The Permanent Pactio also returns, with the strong implication that Negi had sex with both Nodoka and Yue, with the side effect of his Immortality causing their bodies to cease aging.
- In the world of 'ships, Oh My Goddess' Keiichi/Belldandy is the U.S.S. Constitution... And it all started way back when Keiichi thought his wish from the Goddess Relief Agency was just a hoax. Then comes the rather dark twist: The system that enforces the contract has also messed with Keiichi's mind to keep him from having lustful feelings for Belldandy, since Heaven wants to keep mortals and deities separate. Belldandy knew about this all along and said nothing. Then later, it gets bright again when that part is removed and the pair go through testing to stay together.
- Alice and Oz of PandoraHearts actually subvert this. Although Alice is violently protective of Oz, and he treasures her like his "sun", Word Of God says that their relationship is not romantic in nature.
- A major element of Sekirei, especially for Minato and his harem. With a few exceptions, all bonds involve Love at First Sight and are referred to as marriages or engagements by the Sekirei.
- Used rather darkly in Shamanic Princess. The fact that beautiful young women are summoning sometimes handsome young men to be their "Partners" which, despite the name, are distinctly subservient to them doesn't always work out too well. Clear examples are Leon's Unrequited Love for Lena, and the very tempestuous deal between Graham and Tiara.
- Sora and her Princesses from Shitsurakuen.
- Faust and Mephistoples in Frau Faust.
- Vermeil in Gold: Alto needs to summon a familiar in order to advance to the next year in the magical academy, and he ends up finding a grimoire in the school library. Out of it comes Vermeil, a beautiful and seductive female demon, who's more than happy to form a contract with him for freeing her, and the two quickly begin to develop feelings for each other.
- In Codex Alera the Marat bond with an animal, gaining the ability to communicate with it and acquiring some of its abilities, e.g. Dorogo, bound to an immensely strong gargant (giant ground sloth) is even stronger than he looks. Kitai bonds with Tavi, which doesn't seem to do much until he finally comes into his Furies, at which point she can use them too.
- In Nightside, a man made a Deal with the Devil to meet his One True Love, only to learn upon his death and consignment to Hell that she was a succubus contracted to play the part. Thing is, he genuinely loves her, so much so that he gets evicted from Hell with her as his (rather confused) companion. Ultimately, she comes to love him as well, and her Heroic Sacrifice to save his life redeems them both and lets her become an Ascended Demon.
- In Disgaea 2, Adell and Rozalin end up falling for each other after Adell accidentally summons her while trying to summon her father. Though technically, she WAS the one they attempted to summon, considering the target was the Overlord, which she actually is, even if she can't remember it.
- In Duel Savior Destiny Rico and Taiga enter one of these in her route. Though they've already entered the contract before that through fun times for Taiga, it's not really a romance until then.
- Fate/Grand Order: Many of the Servants you can contract with will fall in love with you, to different extents, if you bonded with them (i.e raised their bond points) enough.
- Like in Fate/stay night, Fate/EXTRA has the protagonist (who can be either male or female) being able to bond with and later romance a Servant of their choice, Saber (Nero), Caster (Tamamo-no-mae) or Archer (Nameless). The last one is less overt than the others however.
- Often possible in the Summon Night games.
- In the Warcraft universe, it is implied that this can happen with a warlock and his/her succubus. The succubus will often grow attached to her master, even to the point of being uncontrollably in love with him or her, though the succubus is prone to fits of jealousy.
- Female Revya and Gig can have this in Soul Nomad & the World Eaters if the player gets Gig's ending. After being cursed into sharing a body again, they're told only an act of true love can break the curse. All of their companions are quick to point out they're a perfect match for that.
- In Demonbane, this sort of dynamic rises between Al Azif and Kurou Daijuuji. It's noted to be extremely rare: a sorcerer needs a grimoire bound to him to be considered a true sorcerer, and a grimoire has very limited power without a master. Usually, the grimoires and sorcerers treat each other as tools for their respective purposes, but Kurou treats Al like an actual person, which throws her for a loop and causes her to fall in love with him. Whether he reciprocates depends on the route. Curiously, the only other major grimoire character is also in love with her master, but he doesn't reciprocate at all, being pretty much incapable of love or affection in any form. Until they are both dead, after getting smacked with The Power of Love courtesy of Al and Kurou.
- In Fate/stay night, Shirou accidentally summons Saber as his servant in the Holy Grail War, falling in love with her at first sight, although he doesn't recognize his own feelings at first. Because of the botched summoning, Saber cannot draw magical energy from Shirou the usual way, and is running out of energy for fighting, or even simply maintaining her existence. Rin figures out a way for Shirou to give Saber energy by having sex with her, and Saber agrees to do it out of necessity, but as the war goes on Shirou confesses his love to Saber and tries to persuade her to stay with him, while she wants to keep their relationship strictly contractual because that would conflict with her own mission. By the end of her route, however, Saber tells Shirou that she loves him in return.
- Shiki and Len from Tsukihime. As a Really 700 Years Old familiar without a master, Len needs to form a contract with someone to survive, and Shiki agrees to do so. It just so happens that the most convenient way to do so is through sex (Len being part-succubus might have something to do with that). There isn't suggested to be much actual romance between the two: Len is certainly fond of Shiki afterward, but Shiki doesn't seem to consider her a romantic partner.
- For an actually outright romantic example, there's Shiki and his adoptive sister Akiha. Akiha resurrected Shiki from the dead when they were children using her demonic powers, which turned Shiki into a shikigami. As a result, they are bound together in a similar way to a master and familiar, with Shiki living off of Akiha's life force and their minds and souls being connected. Akiha is deeply in love with Shiki (and has been since they were children), and depending on the story route, Shiki may or may not reciprocate.
- And in the fighting game sequel, Melty Blood, Sion and Riesbyfe are heavily implied, but never quite stated, to have this after Ries is resurrected by the Tatari and made into Sion's sort-of-but-not-exactly familiar.