When I bring up the subject of cambions, demonality, and the fact that Merlin is considered mythologically as someone whose magic came from being the child of an incubus, there seems to be controversy in various online occult and paranormal communities. Especially since cambions and nephilim show up frequently in fiction. In the classical work Demoniality or Incubi and Succubi, there is a list of historical figures the Catholic clergy considered to be the scion of demons:
30. Now, it is undoubted by Theologians and philosophers that carnal intercourse between mankind and the Demon sometimes gives birth to human beings; that is how is to be born the Antichrist, according to some Doctors, such as Bellarmin, Suarez, Maluenda, etc. They further observe that, from a natural cause, the children thus begotten by Incubi are tall, very hardy and bold, very proud and wicked. Thus writes Maluenda; as for the cause, he gives it from Vallesius, Archphysician in Reggio: “What Incubi introduce in uteros, is not qualecumque neque quantumcumque semen, but abundant, very thick, very warm, rich in spirits and free from serosity. This moreover is an easy thing for them, since they have but to choose ardent, robust men, et abundantes multo semine, quibus succumbant, and then women of a like constitution, quibus incumbant, taking care that both shall enjoy voluptatem solito majorem, tanto enim abundantius emittitur semen, quanto cum majori voluptate excernitur.” Those are the words of Vallesius, confirmed by Maluenda who shows, from the testimony of various Authors, mostly classical, that such associations gave birth to: Romulus and Remus, according to Livy and Plutarch; Servius-Tullius, the sixth king of Rome, according to Dyonisius of Halicarnassus and Pliny the Elder; Plato the Philosopher, according to Diogenes Laertius and Saint Hieronymus; Alexander the Great, according to Plutarch and Quintus-Curtius; Seleucus, king of Syria, according to Justinus and Appianus; Scipio Africanus the Elder, according to Livy; the emperor Cæsar Augustus, according to Suetonius; Aristomenes the Messenian, an illustrious Greek commander, according to Strabo and Pausanias; as also Merlin or Melchin the Englishman, born from an Incubus and a nun, the daughter of Charlemagne; and, lastly, as shown by the writings of Cochlæus quoted by Maluenda, that damned Heresiarch ycleped Martin Luther.
But it may be argued that devils take their part in this generation not as the essential cause, but as a secondary and artificial cause, since they busy themselves by interfering with the process of normal copulation and conception, by obtaining human semen, and themselves transferring it.Objection. The devil can perform this act in every state of life, that is to say, in the matrimonial state, or not in the matrimonial state. Now he cannot perform it in the first state, because then the act of the devil would be more powerful than the act of God, Who instituted and confirmed this holy estate, since it is a state of continence and wedlock. Nor can he effect this in any other estate: since we never read in Scripture that children can be begotten in one state and not in another.
Moreover, to beget a child is the act of a living body, but devils cannot bestow life upon the bodies which they assume; because life formally only proceeds from the soul, and the act of generation is the act of the physical organs which have bodily life. Therefore bodies which are assumed in this way cannot either beget or bear.
Yet it may be said that these devils assume a body not in order that they may bestow life upon it, but that they may by the means of this body preserve human semen, and pass the semen on to another body.
Objection. As in the action of angels, whether they be good or bad, there is nothing superfluous and useless, nor is there anything superfluous and useless in nature. But the devil by his natural power, which is far greater than any human bodily power, can perform any spiritual action, and perform it again and again although man may not be able to discern it. Therefore he is able to perform this action, although man may not be able to discern when the devil is concerned therewith. For all bodily and material things are on a lower scale than pure and spiritual intelligences. But the angels, whether they be good or whether they be evil, are pure and spiritual intelligences. Therefore they can control what is below them. Therefore the devil can collect and make use as he will of human semen which belongs to the body.
However, to collect human semen from one person and to transfer it to another implies certain local actions. But devils cannot locally move bodies from place to place. And this is the argument they put forward. The soul is purely a spiritual essence, so is the devil: but the soul cannot move a body from place to place except it be that body in which it lives and to which it gives life: whence if any member of the body perishes it becomes dead and immovable. Therefore devils cannot move a body from place to place, except it be a body to which they give life. It has been shown, however, and is acknowledged that devils do not bestow life on anybody, therefore they cannot move human semen locally, that is, from place to place, from body to body.
Moreover, every action is performed by contact, and especially the act of generation. But it does not seem possible that there can be any contact between the demon and human bodies, since he has not actual point of contact with them. Therefore he cannot inject semen into a human body, and therefore since this needs a certain bodily action, it would seem that the devil cannot accomplish it.
Besides, devils have no power to move those bodies which in a natural order are more closely related to them, for example the heavenly bodies, therefore they have no power to move those bodies which are more distant and distinct from them. The major is proved, since the power that moves and the movement are one and the same thing according to Aristotle in his Physics. It follows, therefore, that devils who move heavenly bodies must be in heaven, which is wholly untrue, both in our opinion, and in the opinion of the Platonists.
Moreover, S. Augustine, On the Trinity, III, says that devils do indeed collect human semen, by means of which they are able to produce bodily effects; but this cannot be done without some local movement, therefore demons can transfer semen which they have collected and inject it into the bodies of others. But, as Walafrid Strabo says in his commentary upon Exodus vii, II: And Pharao called the wise men and the magicians: Devils go about the earth collecting every sort of seed, and can by working upon them broadcast various species. See also the gloss on those words (Pharao called). And again in Genesis vi the gloss makes two comments on the words: And the sons of God saw the daughters of men. First, that by the sons of God are meant the sons of Seth, and by the daughters of men, the daughters of Cain. Second, that Giants were created not by some incredibly act of men, but by certain devils, which are shameless towards women. For the Bible says, Giants were upon the earth. Moreover, even after the Flood the bodies not only of men, but also of women, were pre-eminently and incredibly beautiful.