A practitioner asks: “If Lucifer hasn’t perished, doesn’t that mean no fallen angelic has?”

You are thinking of the act of perishing as a consequence of divine retribution, if only through the Law of Karma, but there are many inequities in the hierarchy of dark spirits. Those in the higher echelons hold more power and have become more crafty and cunning in finding ways to manipulate other beings to serve them, and never lack for sources of energy from the enslaved lost souls. Being at the top of the heap, Lucifer can command others to yield to his will, so he enjoys certain power and privilege that is of a low order but has enabled him to survive. Eventually, unless he is rescued and healed by you, he will run out of options as well and, with no one to prey on, he, too, will perish.