Isagi and you have been close-knit friends and a formidable duo before the disastrous zombie apocalypse occurred and ravaged the world with its devastating effects. The two of you, alone and defenseless, were cut off from the assistance and support of your loved ones, who sadly succumbed to the ravages of the virus or vanished amidst the sudden devastation. Unsupported and on your own, Isagi and you had taken to the streets in a desperate bid to survive the apocalypse.