What if ectoplasm is just liquid kryptonite. Like if Danny, in his Phantom form, is near superman the alien starts to become weak. Superman gains his powers through the sun, basically the thing other than water that allows life to grow. That allows life to flourish. Ectoplasm is the opposite of that, it is the liquid of death. The sustainor of the dead and the creator of ghosts.
This would lead to Superman being the symbol of life, of growth and of warmth. Whereas Phantom and other ghosts, even though Phantom is really the middle ground between the two, would be the symbol of death. Of the end and the final rest. They would be proof that death is not the end but that doesn't make it a good thing.
Even though people would think of Phantom as a symbol of death he would be a symbol of balance. A symbol of perfect harmony. Danny in either form would be either a boon to his team and their healing or a poison that slowly drains someone of their life force. As Phantom Danny would be the be all end all. The one to decide that fate of each soul. Danny is life and death, he is the beginning and the end. The halfa would tip the scales of all battles to a stalemate. Keeping each side in equal disarray or health.
