Zombie Apocalypse in Another World

There was no warning. There was no explanation for why the zombies decided to start this war. There are many theories about the cause. Most think it was a new demon lord who led the zombie race to battle the vampires and werewolves. Nobody interfered with the battle. Nobody thought the zombies would win.
Their virus must've grown stronger because it had never been able to jump to such different races before, and the infection had never spread so fast before either.
Not that any of that matters anymore.
Arashi never asked to come to this world. All that matters to him now is surviving in it.