As Krishna said in the Bhavat Gita "the slayer slays not the slain nor is the slain ever slain by the slayer" you cannot kill the eternal unborn soul for it was not born into the material plane. The Christains call this the Holy Spirit for which they know little of, the Bhudists call this the Atma for which they know little of, the Hindus call this the Atma Parabrahm and the daoists call this the eternal dao. Krisna said "very few will ever hear about he Atma, fewer still will strive to understand it, even fewer will didicate their lives to it (including serving it with kindness) and hardly any will reach its understanding.