->''"No matter how many times I see it happen, it is always cool."''
-->-- '''Mizore Shirayuki''', referring to Kiva's [[SuperMode Emperor Form]]

A masterpiece from the minds of Kamen Rider Chrome and Ten-Faced Paladin, creators of such fics like ''[[FanFic/ShowaAndVampire Showa and Vampire]], [[Fanfic/LoveHinaDoubleTrouble Love Hina Double Trouble]]'', and ''[[Fanfic/KamenRiderOOOTheMetalsOfIkkiTousen Kamen Rider OOO: The Medals of Ikki Tousen]]''. A crossover with ''Series/KamenRiderKiva'' and ''RosarioToVampire'', ''[[http://www.fanfiction.net/s/4579599/1/Rosario_to_Kiva Rosario to Kiva]]'' is one of the most popular of fanfics. The first chapter was published on October 6th, 2008, and ran fifty-five chapters until October 6, 2012, exactly four years. Now there is a [[http://rosariotokiva.wikia.com/wiki/Rosario_to_Kiva_Wiki#Welcome_to_the_Rosario_to_Kiva_Wiki wiki]]

A teenaged Wataru Kurenai enters Yokai Academy in an attempt to escape his crapsack life. He soon encounters the super-cute vampire Moka Akashiya, who takes a quick liking to both him and his blood. He soon creates more friends and foes as the secrets of his heritage are slowly revealed to him - secrets that his harem may very well be connected to.

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!This fanfiction series contains examples of:
* AntiHero: While he was still trying to kill Kiva, Saga wasn't evil to begin with. The proof is in the fact that he saved Kurumu from an incubus and Mizore from a Mind Flayer.
* {{Adorkable}}: Wataru tends to be shy, reticent, and easily flustered around girls. All of that just makes him more attractive to them, particularly once they experience his compassionate nature.
* ArrangedMarriage: A forced type is attempted on Taiga and Mizore. It does not go through. Later played straight with Tagia and Mio. Unlike the canon though, [[PerfectlyArrangedMarriage they have found real romance in each other.]]
* BalancedHarem: Because Wataru is a prince, he can marry all the girls in his harem. The only question that remains is if they are willing to share.
** They are, so now the question is: Who's first wife?
* BattleCouple: With Inner Moka, though it's quite a while before they admit their feelings for each other. Still, they admit it a lot sooner than Tsukune and Moka do in the canon manga or anime. It is eventually upgraded to a BattleHarem.
* TheBerserker: When his Fangire blood is forcibly awakened by Bishop of the Checkmate Four, Wataru descends into this trope, attacking anyone and everyone in his path no matter if they're friend or foe.
* BewareTheNiceOnes: Wataru may be the nicest dhampir ever, but do not mess with people he cares about. You will not end well. At all.
** Do not betray Mizore's trust. You will regret it.
* BigBad: [[EvilGenius Bishop]], after Taiga's HeelFaceTurn.
** [[spoiler: BiggerBad: The previous King/Bat Fangire after Bishop gave his life to revive him in chapter 54.]]
* BigDamnHeroes: Wataru, like any good superhero, is fond of doing this.
* BreakTheHaughty: When Moka's younger sister Kokoa comes on the scene, she thinks very little of Wataru and resents him for getting between her and her "real" big sister, Inner Moka. Kurenai takes over, thrashes her one-on-one as Emperor Kiva, and even gives her a spanking to top things off. [[SubvertedTrope This somewhat backfires]], as Kokoa ends up adoring Kiva just like she adores Inner Moka... and feels the same way toward Wataru as she does with Outer Moka.
** Happens to the Inner Moka after her first defeat against Rook. She was really pissed about being beaten so easily and was steaming about it for a while.
* CainAndAbel: Wataru has this with his half-brother Taiga, King of the Checkmate Four, who considers humans lower than dirt and is also attracted to Moka. Of course, Wataru manages to turn things around and Taiga soon becomes an ally.
* ChristmasEpisode
* ChromeChampion: In Emperor Form, Kiva acquires golden armor with a matching cape, and in quite a glittery shade, too.
* CluelessChickMagnet: Wataru doesn't quite understand what is so particularly appealing about him. The girls around him are more than willing to explain (heh, heh, heh).
* ContinuityCameo: Many Franchise/KamenRider series before and after ''Kiva'' have made cameos (direct and indirect).
** Series/KamenRiderHibiki: In chapter 33 during Kurumu and Wataru's date, the two watch a [[DualWielding purple oni playing a taiko drum]], a [[BlowYouAway trumpet-playing blue oni]], and a [[BladeOnAStick guitar-playing green oni]] doing a street performance.
*** Their organization, Takeshi, was mentioned by Maya in chapter 40 as one of the 13 Mazoku/Demon Clans.
*** Also, Asumu makes an appearance in chapter 42 as a representative of Takeshi. He also fights the Legendorga in chapter 44 as Hibiki, [[spoiler: since the previous Hibiki retired]].
** Series/KamenRiderDenO: Their {{Crossover}} in chapter 39 and during the Legendorga arc.
** Series/KamenRiderDouble: Wataru and the girls visit the Sonozaki Museum in chapter 37 and chapter 40.
* CoolSword: The Garulu Blade, which enables Wataru to transform into a werewolf-based form with increased speed, agility, and reflexes. In Emperor Form, he acquires the Zanvat Sword, which is initially an EvilWeapon controlling him before Wataru's willpower --- with some help from the Arms Monsters --- wins out over it.
* CovertPervert: Mio, appearently.
* DidYouJustHaveSex: Both Kurumu and Gin are able to tell that Moka and Wataru had sex and confront them respectfully.
* {{Dhampir}}: Wataru is a Fandiri, which is the Fangire equivalent of this trope since Fangires are technically a subset of vampires that has gone on a divergent evolutionary path.
* DistaffCounterpart: [[spoiler:Kamen Rider Lady Rey and Kamen Rider Dark Lady Kiva.]]
* DroppedABridgeOnHim: [[spoiler:Shiramine was left behind during the battle against the Legendorga clan. What happened to him after is unknown. Not that Mizore cares. [[MoralEventHorizon Not after what he did]].]]
* FantasticRacism: Bishop's deep hatred for Wataru. He often referse to him as "that bastard half-breed".
* ForgottenChildhoodFriend: Remember the little boy Mizore accidently scared away when she was little? [[spoiler:That was Shiramine, A.K.A. Kamen Rider Rey. Although he did miss Mizore and regreted breaking Mizore's heart, he saw Wataru as an obstacle that must be removed. Bishiop took notice and made him into his [[TheMole mole]]. Needless to say, Mizore did NOT take that kindly.]]
* GoofyPrintUnderwear: Wataru's red boxers have bats on them.
* HaremHero: Wataru is Type 2B.
* HeelFaceTurn: Taiga and [[spoiler:Rey-Kivat]].
* IKnowYouAreInThereSomewhereFight: Moka does this with Wataru on a few occasions, most notably when he's transformed into the Emperor Bat and when Bishop has forced his Fangire blood to the surface to make him an unthinking berserker. Thanks to ThePowerOfLove, it always works.
* InsultBackfire: The Mummy Legendorga does this, countering the Inner Moka's catchphrase:
--> ''"(Know) my place? Girl, I am one of the mighty Legendorga Clan! The most illustrious of all the Mazoku! You are a mere vampire! I know my place quite well! You at my feet bowing like the inferior you are!"''
* LoveTriangle: Wataru/Moka/Taiga before Taiga meets Mio.
** In 1988, its Ageha/Otoya/Tsurara. Sadly, this is what cause the two women to be broken up.
* LoveYouAndEverybody: Despite his reservations, Wataru can't bring himself to hurt any of the girls in his harem by choosing one over the others, such is the depth of his feelings for all of them. Thus, they go with MarryThemAll.
* MagneticHero: For a guy who's so shy, especially around the opposite sex, he sure attracts a lot of girls... and ends up making many of them into friends and even more, despite the nature of their initial encounters.
* MarkedChange: Wataru's Fangire markings tend to manifest when he's ready to transform into Kiva and really wipe the floor with some troublemakers.
* {{Meido}}: Ruby, after the Witch's Knoll arc.
* [[spoiler:OhCrap: Issa Shuzen's reacton after seeing an enraged Maya barge in the castle in chapter 54 ([[WordOfGod Chrome]] states that Maya was the only person he feared aside from Akasha, Moka's mother). Kivat II to a lesser extent.]]
* NiceGuy: Wataru. "Kurenai" is where BewareTheNiceOnes comes into play, but even Wataru himself is not someone you want to push... or else his own righteous fury might just sync perfectly with Kurenai's natural aggression.
* PowerGlows: When first transforming into Emperor Form.
* PerfectlyArrangedMarriage: Taiga met Mio in one of his classes. They became close friends even before it was revealed that she was Queen.
* RescueRomance: How Wataru ends up winning over many, if not most, of the girls in his harem.
* RuleOfThree: [[spoiler:TwoWords: Hat Trick]].
* SecretLegacy: Wataru is the inheritor of the power of Kiva, the birthright of the Fangire King.
* SiblingTeam: With Taiga/Kamen Rider Saga, after Taiga's HeelFaceTurn.
* SixthRanger: [[spoiler:Mizore/Kamen Rider Lady Rey, Kokoa/Kamen Rider Kiva-la, and ''much'' later, Inner Moka/Kamen Rider Dark Lady Kiva.]]
* SpearCounterpart: "Kurenai" to the Inner Moka.
* SuperPoweredEvilSide: Subverted. "Kurenai" is a secondary personality that represents the aggression and bloodlust inherent to Wataru's Fangire side, but he is the farthest thing from evil, just much bolder and more assertive than Wataru tends to be. You could say that he's the male counterpart of the Inner Moka.
* UpgradeArtifact: The Garulu Blade has the same effect on Inner Moka as it does on Kiva, granting her heightened speed and reflexes. We have yet to see what happens when she uses Kiva's other weapons.
* [[SpinoffBabies Teenage Spinoff]]: Wataru is sixteen in the story while he was twenty-one in the canon.
* MarryThemAll: Wataru is presently navigating through this with Moka, Kurumu, Mizore, and Ruby (Yukari is exempted for the time being [[{{Jailbait}} because of her age]]). [[spoiler:It succeeds as shown in the finale, where Masao (Moka and Wataru's son), Kurumi (Kurumu's daughter), and Miyuki (Mizore's daughter) arrive from the future to warn them of the Neo-Fangire threat.]]
* [[spoiler:ThisCannotBe: Bishop's LastWords after he (as the Bat Fangire) was KilledOffForReal in the finale.]]
--> [[spoiler:"NO! NO! HOW CAN THIS...HAPPEN! MASTER WAS SUPERIOR! HE WAS FANGIRE PERFECTION! HE WAS DESTINED TO RULE ALL! HOW? HOW? HOOOOOOOWWW?"]]
* [[spoiler:TookALevelInBadass: Inner Moka becoming Kamen Rider Dark Lady Kiva.]]
* WhamLine: A lot.
** [[spoiler:"That's my mother. I have a portrait of her in my home."]]
** [[spoiler:"Was your father named Otoya Kurenai?"]]
** [[spoiler:"You're lucky that Akasha-chan taught me about her seals in case my sons would need them."]]
** [[spoiler:"I hope you're alright... My Queen."]]
* YaoiFangirl: Both Kokoa and Mio. Though Kokoa is a much more vocal about it.