Legion - Demon Princess Arc

The story focuses on Ichiro Takamura, an average high school student, who ended up getting involved in a war between Angels, Demons, Fallen Angels and Dragons. This all happened after Ichiro is almost killed by a Fallen Angel, who is also hunting down a Demon Princess. After an unexpected incident happened during Ichiro's date with Amata Sakura, who is revealed to be a Fallen Angel, Ichiro is almost killed in this incident. This eventually led to his unexpected involvement in the supernatural war between Angels, Demons, Fallen Angels and Dragons. Upon his involvement, Ichiro then takes on a new role, and his role is to protect his childhood friend, Kaori, who is soon revealed to be the Demon Princess and the future Demon Queen of the Underworld.
Ichiro willingly accepts his fate and decides to do this, even if it costs his life. As the story progresses, Ichiro will fight against Angelic and Fallen Angelic legions, Demon lords, people from the Order of the Sword and the Church as well as the Watchers, and other mythical beings.