Inspite of being a son of Param Purush, why did Niranjan ask for the Jivas? Even if he did so, why did he torture them?

We often hear in the Kathas-Stories that not only the Gods but the Demons as well worshipped hard. However, the only difference was that whereas the Gods asked for the blessings of Lord or sought such powers as could be used for the good of others, the demons asked for such powers as could make them invincible. Moreover, they asked for long lives as well. They used the powers attained through blessings only for torturing others.
Niranjan as well did the same. As he was created by the forceful utterance of sound, he turned like a demon. He worshiped Param Purush and asked for such things as had nothing to do with the good of others. He tortured the Jivas and behaved in a very cruel manner with his brother Kooram as well. His behavior with Adhya Shakti clearly shows that he was a demon and not a noble and virtuous Son of Param Purush.
Nevertheless, though Niranjan imprisoned the souls in bodily cages and gave them all sorts of tortures, yet he couldn’t do so in the real sense as Param Purush had made Souls completely safe and secure from harms. The tortures were, in fact, suffered by Niranjan himself.