The Second Death in (pre-Christian) Greek Literature

The Thesaurus Linguae Graecae does not provide any examples of pre-incarnation Greek writers who use the phrase "the second death."  The only non-Christian Greek author using the phrase that I could find prior to Origen is Plutarch (c. AD 40 - 120).  His "On the Face which appears on the Orb of the Moon" is the one work that I found with the phrase.  I offer the following translation by Arthur Octavius Prickard (1843-1939)(pp. 44-45):

XXVII. When I marvelled at this, and asked for clearer statements, he went on : — " Many tales, Sylla, are told among the Greeks about the gods, but not all are well told. For instance, about Demeter and Cora, they are right in their names, but wrong in supposing that they both belong to the same region ; for the latter is on earth, and has power over earthly things, the former is in the moon and is concerned with things of the moon. The moon has been called both Cora and Persephone, Persephone because she gives light, Cora because we also use the same Greek word for the pupil of the eye, in which the image of the beholder flashes back, as the sunbeam is seen in the moon. In the stories told about their wanderings and the search there is an element of truth. They yearn for one another when parted, and often embrace in shadow. And what is told of Cora, that she is sometimes in heaven and in light, and again in night and darkness, is no untruth, only time has brought error into the numbers ; for it is not during six months, but at intervals of six months, that we see her received by the earth, as by a mother, in the shadow, and more rarely at intervals of five months ; for to leave Hades is impossible to her, who is herself a ' bound of Hades,' as Homer well hints in the words, (Od., ix, 563.) 'Now to Elysian plains, earth's utmost bound.' For where the shadow of the earth rests in its passage, there Homer placed the limit and boundary of earth. To that limit comes no man that is bad or impure, but the good after death are conveyed thither, and pass a most easy life, not, however, one blessed or divine until the second death."

Based on where this quotation ends, at the end of section XXVII, one might think that the idea of "the second death" was one that was well-established in Greek mythology/religion already. The way that Plutarch continues, however, suggests otherwise:

 XXVIII. "But what is that, Sylla?" "Ask me not of these things, for I am going to tell you fully myself. The common view that man is a composite creature is correct, but it is not correct that he is composed of two parts only. For they suppose that mind is in some sense a part of soul, which is as great a mistake as to think that soul is a part of body; mind is as much better a thing and more divine than soul, as soul is than body. Now the union of soul with body makes up the emotional part, the further union with mind produces reason, the former the origin of pleasure and pain, the latter of virtue and vice. When these three principles have been compacted, the earth contributes body to the birth of man, the moon soul, the sun reason, just as he contributes light to the moon. The death which we die is of two kinds; the one makes man two out of three, the other makes him one out of two ; the one takes place in the earth which is the realm of Demeter, and is initiation unto her, so that the Athenians used in ancient times to call the dead 'Demetrians,' the other is in the moon and is of Persephone; Hermes of the lower earth is the associate of the one, the heavenly Hermes of the other. Demeter parts soul from body quickly and with force; Persephone parts mind from soul gently and very slowly, and therefore has been called ' Of the Birth to Unity,' for the best part of man is left in oneness, when separated by her. Each process happens according to nature, as thus (Plato, Timaeus, end.): — It is appointed that every soul, irrational or rational, when it has quitted the body, should wander in the region between earth and moon, but not all for an equal time; unjust and unchaste souls pay penalties for their wrong doings; but the good must for a certain appointed time, sufficient to purge away and blow to the winds, as noxious exhalations, the defilements which come from the body, their vicious cause, be in that mildest part of the air which they call 'The Meadows of Hades'; then they return as from long and distant exile back to their country, they taste such joy as men feel here who are initiated, joy mingled with much amazement and trouble, yet also with a hope which is each man's own. For many who are already grasping at the moon she pushes off and washes away, and some even of those souls which are already there and are turning round to look below are seen to be plunged again into the abyss. But those which have passed above, and have found firm footing, first go round like victors wreathed with crowns of feathers called 'crowns of constancy,' because they kept the irrational part of the soul obedient to the curb of reason, and well ordered in life. Then with countenance like a sunbeam, and soul borne lightly upwards, as here by fire, in the air about the moon, they receive tone and force from it, as iron takes an edge in its bath ; for that which is still volatile and diffuse is strengthened and becomes firm and transparent, so that they are nourished by such vapor as meets them, and well did Heraclitus say that 'Souls feed on smell in Hades.'

It is interesting to see a purgatorial concept in Plutarch (the final highlighted portion above).  However, the main point is to note that the "second death" in Plutarch is a second separation.  Not this time between corporeal and incorporeal, but between two incorporeal aspects of man: mind and soul.