Ga-Rei -Zero

Life is slightly depressing and normal for high-schooler Kensuke Nimura - except that he can see ghosts. This ability generally hinders him more than it helps him, until he encounters Kagura Tsuchimiya while being pursued by evil spirits. They accidentally kiss and fight off the spirits together. The next day, she transfers into his class. Kagura is an agent of a government agency that defends the public against supernatural enemies. She wields a Ga-rei, a spirit beast that kills these spirits. Kensuke's spiritual awareness and his attraction to Kagura forces him to follow her to the agency, where he is recruited to fight the supernatural.

Yomi arc

Their first enemy is Yomi Isayama, an old friend of Kagura's, now an evil spirit due to a stone known as the sesshōseki. Also introduced is another old friend, the perverted Izuna Noriyuki. She tries to release an ancient immortal demon sealed under Tokyo. The Agency manage to stop her after a long battle, resealing the demon and killing Yomi in the process. A mysterious boy removes her sesshōseki, and disappears.

Juugondou arc

The next story arc concerns the re-emergence of a sect known as the Juugondou and its heir, Shizuru Imawano. She encounters and alternatively threatens and flirts with Kensuke, angering Kagura. Soon, it turns into a contest between her and Kagura as to who can collect more sesshōseki, with Kensuke as the prize. The pressure is building as Kagura starts losing control of her Ga-rei Byakuei, and the Juugondou arrive in full force. Shockingly, Shizuru's long-lost sister Setsuna arrives, kills her father and takes over the Juugondou. She attacks and demolishes the Agency, and the government try to distance themselves from the Agency for fear of revealing secrets to the public. Kagura, Kensuke, Kyouko and Iwahata survive, and meet Izuna and Shizuru at an agency hideout.