Nephilim (manhwa)

Nephilim is a Korean manhwa written and illustrated by Ryu Kum-chel, author of Ares. The story focuses on a boy, John, who is possessed by an angel, Michael.
Setting.
Nephilim takes place in a world where angels and demons (fallen angels) are constantly at war with one another. When demons appeared, they attacked and harassed humans. In return, the angels came down from Heaven to defend the humans. To back up their forces and continue the fight on earth when they fought in Heaven, the angels and demons granted certain humans abilities to fight in their stead. These humans became the Heavenly Knights Corps and Darkness Knights Corps. While the Knights of Heaven only consist of exceptional individuals, the Knights of Darkness accept just about anyone, which is why the Darkness Knights Corps vastly outnumbers the Heavenly Knights Corps.
One other group exists along with the angels and demons- the nephilim. The nephilim are the offspring of angels and humans. Both the parents and the children are hunted vigorously by the angels. The human parents and the nephilim children are killed, while the angel parents are captured to be reeducated.
The angels, demons, knights, and nephilim fight by summoning weapons known as "Apoca". Apocas normally take the form of innocuous pieces of jewelry on the bodies of the fighters, and can be summoned as weapons at any time. The strength of the Apoca depends on the strength of the owner and the amount of ether (a form of energy) sent into it.
Plot.
The story begins when John, a slave for nobility, is attacked by ruffians. About to be killed, John is saved when Michael, an angel, falls from the sky after fighting demons. Michael forms a bond with John, lending him his strength so that they both can survive. Now on the run from angels, demons, and knights, John must learn from Michael how to harness his new power. Even while fleeing, John finds himself drawn into the most recent clash between the angels and demons, the 6th Armageddon.