Lost Angel (Shitsuraku Tenshi)

Higuri You 

Bonita Comics special 
ISBN 4-253-15783-1 
 
 
We're at a Catholic mission school and we open on a scene of several large boys bullying the head boy of the school. (This seems to be a diehard fantasy among mangakas.) He's rescued by a tight-lipped boy in black who merely says that the bullying was destroying his nap. Head boy is Makise Ryou, boy in black who always wears gloves is Senkouji (thousand rays earth) Gunta (army snake)- whose name, Ryou remarks, is half angelic and half demonic. As is Gunta himself, of course. No spoilers if I tell you he's the fallen angel Lucifer in human form, who weilds the Sword of God, and whose mission is to find his former followers, the other fallen angels, and release them from their self-imposed damnation. 
One fallen angel, Valvert, is currently being worshipped in secret by the nuns of the school, and Ryou's younger brother is also a convert to the sect. 
Feeling inferior to his brother and wanting power for himself, Sakae provides living sacrifices for the nuns (the school rabbit buys it, as does a black cat.) But then the demon requires a perfect human sacrifice, and who more perfect than Sakae's brother the head of the school? Needless to say, in the end good triumphs- uh, well, *evil* triumphs- uhh, well Gunta in any case takes off those gloves to reveal his skeleton hands, plunges the sword into Valvert's demon body, and restores him to angelhood. 

The second story deals with a young girl, Tsukasa, whom Ryou finds in shock after she has stumbled on a savagely hacked corpse. He calls the police, takes her to the hospital and walks her home. The two begin to fall in love. But Tsukasa has a jealous older brother who tells Tsukasa 'You belong to me.' (Yes, the famous 'Omae wa ore no mono da.') 'I made you. I gave you life.' He did, because he too is a fallen angel; and when Gunta is finished with him, of course Tsukasa's life ends too. 

In the final story Gunta seems to have reverted to his demon form. He kills several people, word of which comes to Ryou through Father Schmidt, the (quite stunningly bishounen looking) German priest/exorcist at the school. Ryou naturally has been unable to stop thinking of Gunta and wondering where he is- which demons he's purifying now etc- and refuses to believe what Schmidt tells him. And in fact Gunta is merely being possessed by one of his former followers, Satanel, who is determined to bring Lucifer back to what he/she/it thinks is his proper role. (Satanel's sex is uncertain because he/she etc takes over people's bodies and lives in them. She starts as a woman and then grabs Fr. Schmidt's altar boy.) She has planted a seed in Gunta's body that makes it do what she wishes. However the good father is determined to dispose of Gunta with a silver bullet: but Ryou throws himself on the gun instead, at which his true nature reveals itself. True nature is a spoiler which is included at the bottom of the page. 

Ryou is the angel Michael, Lucifer's twin older brother, his other half. 'That's why I was always drawn to him.' Gunta/Lucifer assumes angrily that Michael took human form to keep an eye on him, but it was in fact to give Lucifer his wings when he most needs them- which he does with a kiss, thus purifying Lucifer himself. After which Lucifer is still hunting his former followers and Michael is still a schoolboy, but hell...