Rosario + Vampire

Plot
Tsukune Aono is a normal high school teenager, who is unable to get into any school due to his poor grades. However, he gets enrolled to a private school called Yokai Academy (which requires no entrance exam). When he arrives at the school, he soon discovers Yokai is a secret school for monsters disguised as humans, and any human who finds out about its existence will be killed without mercy. Tsukune fears for his life, believing his admission into Yokai a mistake. His luck soon changes when he quickly becomes friends with a beautiful girl Moka Akashiya who turns out to be a vampire attracted to the sweet taste of his blood and sometimes biting Tsukune on the neck when the chance seems right. Moka was upset upon discovering Tsukune's human identity, but realizes he's the first real friend she had ever made in her life. Despite Moka's vampiric nature, she is a kind girl and Tsukune quickly falls for her, and ultimately decides to stay at Yokai, despite the various dangers while hiding his human identity from everyone else. Tsukune soon discovers when he removes the rosario around Moka's neck, she transforms into her true vampire form, being stronger and more powerful than almost any other creature at the school, and Tsukune is the only person who can remove it. However, "Inner Moka" has an entirely different personality, often cold and merciless, and thus the rosary is only removed in dire emergencies.

As the school year continues, Tsukune becomes involved with other students who start out as enemies, but who are won over into becoming his friends: Kurumu Kurono, a busty succubus; Yukari Sendo, an eleven-year-old witch; Mizore Shirayuki, a yuki-onna (a teen version of the legendary snow woman of Japanese folk tales) who stalks Tsukune, believing them to be soulmates; Ginei Morioka, a perverted skirt-chaser of a werewolf who is a second-year student and president of the school's Newspaper Club; and Ruby Tojo, a witch from the human world. However, after Tsukune befriends each of the girls, they become friendly rivals along with Moka, vying for Tsukune's affections, and later most become members of the school's Newspaper Club with Tsukune and stand by him even after they learn that he is really a human. Together they wind up fighting against a variety of enemies within the school body, be it students or teachers, who try to use their monstrous powers to bully or control one or more of the group for their own selfish or destructive ends.

Later on in the second manga serialization, Kokoa Shuzen, Moka's younger half-sister, appears. And, as time goes on, they learn about the dangerous organization Fairy Tale, which seeks to destroy the human world and must do battle against them to keep the school and both the monster and human worlds safe; Tsukune also starts to undergo changes that truly solidify his role as the link between the human and monster worlds. Through body modification, Tsukune gains the ability to wield sorcery and control the vampire blood Moka gave him, but the secret of this blood may still cost Tsukune his humanity if it goes completely out of control.

Eventually, it is revealed the Three Dark Lords Akasha Blooodriver (Moka's Mother), Master Tohofuhai and Tenmei Mikogami (Yokai Academy's headmaster) defeated and sealed a powerful monster named Alucard, which tried to destroy the world 200 years ago and shared the same bloodline as Moka and her mother. The rosario is also revealed to seal Moka's true personality and power away (meaning Outer Moka is fake), in order to keep Alucard contained. To awaken him, Fairy Tale, under Gyokuro Shuzen's (Moka's stepmother) command, kidnaps Moka. During the Newspaper club's attack on Fairy Tale HQ in an attempt to rescue her, the rosario's final secret is revealed; it's meant to control Alucard if he ever awakens. However, Tohofuhai later reveals the rosario actually synchronises with the essence of Akasha inside Alucard, with the end result being Gyokuro Shuzen's demise. At that moment, the Masked King (Fairy Tale's true leader) appears before the Newspaper Club, revealing himself to be Miyabi Fujisaki, who in turn is a clone of Alucard's original vampiric appearance, created shortly before he was sealed. Miyabi/Alucard proceeds to reveal that he manipulated both sides to do battle with one another, in order to access whether the Rosario could control his main body.

Despite the group's efforts, Fairy Tale HQ ends up crashing into the human world, where the original Alucard once more begins trying to destroy humanity; however, Mikogami manages to send most of the humans in the area away. The Rosario is also heavily damaged beyond the point of repair by Miyabi to ensure Alucard cannot be sealed again, leaving Outer Moka "dying"; faced with this, both she and Tsukune reveal their love for each other and share a kiss. While Alucard is fought by both humanity and monsters alike, Aqua Shuzen (Moka's stepsister) attempts reviving her by giving her blood; however, Moka requires more than Aqua can give to her. Tsukune decides to become a true vampire, so he can save the woman he loves.