Seven Mortal Sins

Lucifer, a former Archangel and head of the Seven Heavenly Virtues, is cast out of Heaven after defying God's will. During her fall, she crashes through a high school church's roof, where she's spotted by Maria Totsuka. Lucifer then descends into Hell, where she's found by Leviathan, an aspiring Demon Lord and fangirl, who joins her in a bid to overthrow the Seven Sins - the authorities of Hell, led by Belial.