So the Pure Soul will be killed before the official reappearance of Imam Mahdi (a). The Imam can stop that, but he doesn’t have permission from Allah to do so. The Pure Soul will be unjustly killed, and Allah will allow that to happen just like he allowed for Imam Hussain (a) to be unjustly killed. It’s a trial for everyone. As for the Pure Self, he will achieve martyrdom and Allah will grant him a higher level. And as for those who will kill him, Allah will punish them even more for their evil.