Nations war in isekai world

This story is about 20 years old guy named Kazuki.His life is so boring.He don't have girlfriend or anyone and he lives alone.But one day after he buy something to eat he was hit by a car and immediately die or he think so.He was awake in isekai world where is war between four nations.Will his life have adventure for the first time in his life?or will he die in the insane war between four strongest nations in that world?