Wikipedia: "The philosophers called Neoplatonists did not found a school as much as attempt to preserve the teachings of Plato...The concept of the One was not as clearly defined in Plato's Timaeus (the good above the demiurge) as it later was by Plotinus' Enneads: however the passage in Plato's Republic (509c) in which the Sun is said to symbolize The Good (or the One) can be seen as ample justification for the late Platonist's view of the One-for here Plato calls The Good, "beyond essence," especially when this is placed alongside the range of attributes denied of the One in the Parmenides. The afterlife Socrates defines in Phaedo is also different from the afterlife of the person or soul in the Enneads. The soul returns to the Monad or One in Plotinus' works. This is the highest goal of existence, reflected in the process of henosis. In both the Enneads and Phaedo there are different afterlives: one could be reincarnated, one could receive punishment, or one could to to Hades to be with the heroes of old. This last one for Socrates was the highest ideal afterlife. This is in contrast to Neoplatonism's ideal afterlife of returning to the One or Monad. However, what is said in the Phaedrus (248c-249d) reconciles these two apparently conflicting views: for Socrates in this dialogue shows that a movement from life to life (including periods in Hades) is part of a much greater cycle that culminates in perfection and a divine life." Plotinus is a very important person in Neoplatonism. Even though his teacher, Ammonius Saccas, was said to have founded Neoplatonism, it is Plotinus' Enneads that are the primary and classical document of Neoplatonism. To Plotinus, the individual daimon wasn't anthropomorphic, but instead, a living psychological principle that dwells within us and is transcendent to us. Here Plotinus appears to be in agreement with Dr. Carl Jung's later work-that there are beings (daimons), archetypes and a psyche beyond ourselves. Here is a bit of what Jung thought about his own personal daimon Philemon: "Philemon brought home to me the critical insight that there are things in the psyche which I do not produce, but which have their own life...I held conversations with him and he said things which I had not consciously thought...He said I treated thoughts as if I generate them myself but in his view thoughts were like animals in the forest, or people in the room...It was he who taught me psychic objectivity, the reality of the psyche." Dr. Carl Jung, Memories, Dreams, Reflections, pp.208-209.
The Syrian Neoplatonist Iamblichus (d. 326 AD) also added greatly to the study of daimons, in fact, modern investigators of the paranormal could learn a lot from the distinctions he makes between "phasmata." "For instance, while phasmata of archangels are both "terrible and mild," their images "full of supernatural light," the phasmata of daimons are "various and dreadful." They appear at different times...in a different form, and appear at one time great, but at another small, yet are still recognized to be the phasmata of daemons." As we have seen, this could equally well describe their personifications. Their "operations" interestingly, "appear to be more rapid than they are in reality" (an observation which might be borne in mind by ufologists)." Patrick Harpur, Daimonic Reality, p.39.