I finished this series a while ago, but was unable to write it up because every time I attempted a thoughtful, coherent analysis, the content I was trying to analyze was so deliciously demented, so carefully foreshadowed yet totally insane, that my head exploded.
So I will not analyze. Perhaps someone else can analyze in comments. I will merely provide a highlight reel. And, in case this persuades others to persevere beyond the awful and incoherent first volume, this is the kind of series where it's not all that spoilery to mention that a fleet of flying cannibal zombie angel embryos is sent out to destroy the universe. Also, the art is jaw-droppingly beautiful, especially on the covers.
Volume 12: Zaphikel, a kindly bespectacled angel, helps Setsuna storm Heaven to rescue Sara, who is being held captive by the supremely creepy veiled angel Sevothtarte. Sara rescues herself by convincing her sweet, dim, perenially victimized maid to dress up as her. After viewing the Mengele-like mad scientist laboratories of Heaven, Setsuna escapes on the back of a flying whale. Setsuna and Sara have a touching reunion. But, amazingly, Sara realizes that her incestuous true love is not worth screwing over other people, and goes back to rescue her maid.
Volume 13: Kira's back! Always the highlight of a volume so far as I'm concerned. He, Katan, and Kurai fly around on a winged brontosaurus. Later, Kira appears in some uniform and looks extremely hot. But then, he always does.
Sevothtarte captures Zaphikel and threatens to cut off his wins, which would transform him into a cannibal ghoul.
ZOMG! Sevothtarte is secretly Lailah, the angel Zaphikel was in love with like, ten volumes back, who was raped and then evilly blamed for it and then blamed Uriel (I think) and then apparently went crazy and evil and took over Heaven!
ZOMG! Zaphikel's wings really did get cut off! He really is a cannibal angel ghoul!!! We see him ravenously gnawing some random rotting skull!!! He tries to eat the shoulder of Raziel, the young angel who's his surrogate son!!! But Raziel loves him so much he's willing to be eaten.
(I read this volume in the waiting room of a psychiatrist's office (not one I was seeing myself, it's a long story), and visibly alarmed the waiting patients by laughing maniacally, then trying to stifle it, which just caused my eyes to bulge in a disturbing manner.)
Volume 14: Adam Kadamon aka Saraphina aka the Holy Hermit appears and reveals that Raziel is Zaphikel's biological son, taken as an embryo and raised in an incubator. I forget why. Raziel kills Zaphikel as the ultimate act of love. Unless letting Zaphikel eat him was that. It's so hard to choose.
And then there's a lot of running and shouting and decapitated heads. Sara is threatened with having her brain removed. But all I care about is that Rosiel kills Kira-- a process which involves lots and lots of drawings of Kira bleeding and grimly determined and hot. He has a touching exchange with Setsuna, then explodes. This causes a small apocalypse, because...
Kira is not only secretly Alexiel's demon sword Nanatsusaya, he is also secretly Lucifer!