Chrno Crusade

At the height of the Roaring Twenties, jazz is king, bootleg liquor flows freely, and the mob rules the streets. It is a time of prosperity, luxury and decadence, and the division between rich and poor grows even wider in the wake of the First World War. But it is at such times of great change and upheaval that the dark things that lurk below the world of man can come to the surface… and so, it’s up to the Order of Magdalene- or more specifically, its energetic, bumbling operative Sister Rosette Christopher and her soul-bound devil partner, Chrono – to fight the demonic threats appearing with increasing regularity across America. But a shadow tinges both Rosette and Chrono’s past, which drives them on to fight all the harder as they search for Rosette’s lost brother, Joshua, taken from her by the sinner, Aion, a devil who shares a dark and bloody history with Chrono, and seeks nothing less than to overthrow Heaven and Earth.

The manga and anime initially start out similar but halfway through their respective story lines the two plots diverge, creating different courses of events and endings. The characterization of some the characters, including Rosette and Aion and their roles in the story were changed in the adaptation of the manga. Much of the story is driven by the individual pasts of the main characters and the complex relationships between them.

content taked from wikipedia