The world of Yozakura Quartet is actually not one, but two worlds: one of humans, and one of youkai. Despite appearing mostly human, youkai may have animal like physical traits, along with a number of special abilities. Normally youkai are confined to their world, but some have found their way into the realm of humanity. As a symbol of peace, and a bridge between the two realms, a city was constructed within the protective barrier of seven magical trees, otherwise known as the Seven Pillars. This city of Sakurashin is home to both humans and youkai, with the peace between them maintained by the Hizumi Life Counseling Office. The director of this office is Akina Hiizumi, a teenager with the inherited family ability to perform “tuning,” which can send harmful youkai back to their world permanently. He is aided by a group of girls, including the town’s 16 year old youkai mayor, Hime Yarizakura, their town’s announcer and resident telepath, Ao Nanami, and Kotoha Isone, a half-youkai who can summon objects just by stating the object’s name. As new residents enter and mysterious events begin to take place, this quartet of protectors and their closest friends must continue to guard the city of Sakurashin, and maintain the fragile balance of peace between humans and youkai.

Second Youkai Watch movie.

Throughout history, an elite group of shrine maidens known as "Toji" have saved the world from "Aratama," strange and malevolent beings bent on destroying humanity. In modern times, these warriors have been assigned to a special police squad to exterminate Aratama. The government has also set up five elite schools across the country to provide young girls the necessary sword fighting skills to eradicate these monsters and eventually join their fellow Toji in protecting the world. A student of one of those five schools, Kanami Etou is chosen to represent Minoseki Academy in a sword fighting tournament, where she meets the mysterious Hiyori Juujou. Although Kanami and Hiyori rise to the top of the tournament, their battle takes an unexpected turn, throwing the world of the Toji into chaos. Likely that the Toji are facing betrayal from within, the two are forced to flee the tournament, clashing with former comrades on the way. [Written by MAL Rewrite]

Running into your new stepsister in the bathroom is not the best way to make a good first impression, which Basara Toujou learns the hard way. When his father suddenly brings home two beautiful girls and introduces them as his new siblings, he has no choice but to accept into his family the Naruse sisters: busty redhead Mio and petite silver-haired Maria. But when these seemingly normal girls reveal themselves as demons—Mio the former Demon Lord's only daughter and Maria her trusted succubus servant—Basara is forced to reveal himself as a former member of a clan of "Heroes," sworn enemies of the demons. However, having begun to care for his new sisters, Basara instead decides to protect them with his powers and forms a master-servant contract with Mio to keep watch over her. With the Heroes observing his every move and the constant threat of hostile demons, Basara has to do the impossible to protect his new family members. Moreover, the protector himself is hiding his own dark secret that still haunts him to this day... [Written by MAL Rewrite]