Very limited information is available, therefore the following is to be taken with care.
Rakshasas is the name for a race or class of adverse spiritual entitities (not perceptible to physical eyes) also called 'seducers of Mankind', that represent the enemy of the normal evolution of mankind and the planet Earth.
These adverse beings have been called rakshasas or asuras in the Indian, kabiri(m) in the Egyptian, and Titans in the Greek cultural ages and mythology. Rudolf Steiner usually uses the term Asuras.
A race of demonic beings was created as a result of 'sinful' interaction between remaining Sons of God of the Abel line 'akin to the divine', and the daughters of the worldly Cain line, the two streams or subraces of Mankind. These beings acted seductively upon the human race and caused its downfall in the Atlantean epoch through rise of black magic. They continued to influence human desires until the time of Christ.
Black magic represents the opposite of white magic, the good: it is the mis-use of spiritual powers by and for the I at the expense of other life.
When Christ descended into Hades or Hell, he was confronted there by spiritual beings, the Rakshasa beings. Christ-Jesus was able to bring them into a state of paralysis, unable to move, because he could oppose them from two sides. This was possible due to the dual nature of Christ-Jesus: the human physical chela nature and the spiritual Christ nature. Thereby he banished the 'enemies of mankind' into chains until this 'antichrist' makes his appearance again around the 20th century. Nevertheless the fight against the Rakshasas remained after the MoG and into the middle ages. On that basis we can state struggle against the Rakshasas remains a challenge for mankind upto today.
Lecture coverage and references
Man: fragments of forgotten history (1885), states in Chapter 11
Rakshasas (demons), souls or astral forms of sorcerers, men who have reached the apex of knowledge in the forbidden art. Dead or alive, they have, so to say, cheated Nature, and will defy the order of the general evolution until our planet goes into obscuration, when they will have to turn round and fall into the main current, and have a fresh start in the course of life.
This vile art was at its height during the close of the Atlantean race period, when the everlasting struggle between the black magicians and the Adepts of the Good Law raged most fiercely.
Sorcerers and black magicians, the most powerful of those vile fraternities, attain at the conclusion of a great cycle of activity, what is called Avitchi-Nirvana. At the beginning of the next period of activity they commence a nameless life of spiritual wickedness, to be ended only at the next period of rest. The name of these beings of misery and horror, the cursed alike of man and god, is never pronounced or written, but they have nothing to do with the mortals who pass through the seven spheres.
These are the habitants of the eighth sphere, which has sixteen grades. In the first fourteen of these the entity loses, aft& prolonged periods of suffering, its seven astral and seven spiritual senses. The mysteries of the last two grades are never communicated outside the sanctuary of initiation.
It may be stated, however, that from the last, the entity, having lost the accumulated vile energy of its past, emerges as a new individuality, to begin a new course from the lowest rung of the ladder of life.
1904-06-10-GA093 is the key lecture extract
You will now understand how it is that the episode of Cain and Abel falls into the period between Adam and Seth. A new principle entered into mankind, the principle of heredity, the original sin consisting of being dissimilar to the generation which had gone before.
But there still remain some Sons of God. Not all of those belonging to the Abel line were eradicated. And now we see what took place when to the question: ‘Where is Abel, thy brother?’ Cain answered: ‘Am I my brother's keeper?’ No man would have said that previously. That can only be said by an understanding which reacts as though acoustically to the spiritual. Now the principle of struggle, of opposition, is added to the principle of love; now egoism is born: “Am I my brother's keeper?”
Those who still remained of the Abel line were Sons of God, they remained akin to the divine. But they now had to guard themselves against entering the earthly sphere. And from this resulted what was to become the principle of asceticism among those who dedicated their lives to the service of God. It became a sin for such a dedicated one to have anything to do with those who had committed themselves to the affairs of earth. It was a sin when 'The Sons of God saw the daughters of men that they were fair’ and took them wives; they took them wives from the daughters of Cain.
From this union resulted a race of men which is hardly even mentioned in the published books of the Old Testament, but is only hinted at; it is a race that is not perceptible to physical eyes. It is called ‘Rakshasas’ in occult language and is similar to the ‘Asuras’ of the Indians. It consists of demonic beings who really did exist at one time and who acted seductively upon the human race and caused its downfall.
This flirtation of the Sons of God with the daughters of men produced a race which worked particularly seductively upon the Turanians, the members of the fourth sub-race of the Atlanteans, and led to the destruction of humanity. Some things were preserved and carried over into the new world. The Deluge is the flood which destroyed Atlantis. Men who were seduced by the Rakshasas disappeared by degrees.
And now I have to tell you something which will in any case appear extraordinary to you, which is particularly important. It has been an occult mystery for the outside world for many centuries and will seem incredible to most people, but is nevertheless true. I can assure you that every occultist has often convinced himself of its truth through what is called the Akashic Record. But so it is.
These Rakshasas were real beings, they really existed — actively and effectively — as seducers of mankind. They continued to influence human desires until the time when Christ incarnated in Jesus of Nazareth and the Buddhi principle itself became present on the earth in a human body. Now you may believe it or not: this is something of cosmic significance, of significance which reaches beyond the earthly plane. It is not for nothing that the Bible expresses it thus:
‘Christ descended into the forecourts of Hell.’
It was not human beings He met there, He was confronted by spiritual beings. The Rakshasa beings were brought thereby into a state of paralysis and lethargy! They were at the same time kept in check so that they became unable to move. They could only be lamed in this manner because they were being opposed from two sides. That would not have been possible if there had not been two natures combined together in Jesus of Nazareth: on the one hand the old Chela nature, deeply connected with the physical plane, which could also work effectively on the physical plane and through its power could hold it in balance: on the other hand there was Christ Himself who was a purely spiritual being. That is the cosmic problem which is fundamental to Christianity. Something occurred at that time in occult spheres; it was the banishment of the enemies of mankind which has its echo in the Saga of the Antichrist, who was put in chains but will make his appearance again, if not opposed once more by the Christian principle in its primal force.
The whole occult striving of the Middle Ages was directed towards nullifying the effect of the Rakshasas. Those whose vision extends to the higher planes have long foreseen that the moment when this could happen might be at the end of the nineteenth century, at the transition from the nineteenth to the twentieth century.
Nostradamus, .. was able to foretell the future. .. In ‘Centuries’ by Nostradamus (Century 10, 75) the following prophecy can be found: At the close of the nineteenth century a Hermes Brother will come from Asia and bring unity to mankind. The Theosophical Society is nothing less than a fulfillment of this prophecy of Nostradamus. The annulment of the Rakshasas and the reestablishment of the primal mysteries is an aim of the Theosophical Society.
You know that Jesus Christ remained on the earth for ten years after His death. The Pistis Sophia contains the profoundest theosophical teachings, it is much more profound than Sinnett's Esoteric Buddhism. Jesus incarnated again and again. His task was to renew the mystery wisdom. This is no mere fact of cultural or historical interest, but it is the fact I have described to you, which is well known to all occultists, namely, the struggle against the Rakshasas. You see there is a deep and important occult secret lying hidden therein.
In the Secret Doctrine by Blavatsky also some cryptic clues are offered in several places. Not all of them are listed here as they not of relevance, but the following seem to be consistent with the overall picture.
.. it is only from the time of Atlantis that one ought to speak of Man, since only the fourth race was the first completely human species. However these brown and yellow giant races were much larger in size than we are now. ..
It is chiefly that race which became "black with sin" that brought the divine names of the Asuras, the Rakshasas and the Daityas into disrepute, and passed them on to posterity as the names of fiends.
For the Suras (gods) or Devas having incarnated in the wise men of Atlantis, the names of Asuras and Rakshasas were given to the Atlanteans; which names, owing to their incessant conflicts with the last remnants of the Lemurian race and the "Sons of Will and Yoga," have led to the later allegories about them in the Puranas.
"Asura was the generic appellation of all the Atlanteans who were the enemies of the spiritual heroes of the Aryans (gods)."
Whereas the Rakshasas are generally translated by "Evil Spirits" and "the enemies of the gods," which identifies them with the Asuras.
and another quote of Secret Doctrine
The first atlantean races, born on the Lemurian continent, separated from their earliest tribes into the righteous and unrighteous, into those who worshipped the one unseen spirit of nature (pantheists) the ray of which man feels within himself .. and those who offered fanatical worship to the spirits of the earth, the dark cosmic anthropomorphic powers, with whom they made alliance. These were the earlies gibborim, the might men of renown in those days (Genesis 6), who became with the fifth race the kabirim: kabiri with the Egyptians and Phoenicians, titans with the greeks, and rakshasas and daityas with the indian races.
Contemplation about re-appearance
On the positive side: if the re-appearance of the enemies of mankind was foreseen or expected end of 19th or early 20th century, then this most probably - let's hope so - already happened in the last 100 years between 1920 and 2020. This topic relates to topic of the physical incarnation of Ahriman (with lots of speculation about this), as well as the impact of the 'Beast' from the Book of Revelation each 666 years.
It is an interesting exercise to contemplate where we could find this influence, which influences have thrown humanity of course, or rather represent major challenges for its righteous development. Some and actually most sources like to speak of the second world war .. and given the two world wars are related as one this could be seen as one main event with major impact. However a second candidate is the rise of the mobile computing (with the personal computer, mobile phone and the smartphone all in a few decades, say the work of a single generation) with the selfie culture. This evolution drastically pulled and pulls Mankind out of the physical world and direct human interaction, and rechannels much mental and emotional energy into a virtual world (of the small screen) consisting of or owned by a network of (computer) machines. Whereas the elementals related to computer machines are easily linked with Ahriman, the selfie may be seen as a symbol of overdoing I-centric egotism at the cost of less attention for other human beings (which could be seen as an Asuric symptom).
Relation with Luciferic - Ahrimanic - Asuric beings, the rise of black magic and evil
Rudolf Steiner would certainly not have used the terminology he used in the lecture quoted above, if the entities belonged to the Luciferic or Ahrimanic class. Rudolf Steiner usually uses the term Asuras and only once linked in the term Rakshasas in an early lecture in 1904, whereby we can better trace the origin to the Abel/Cain streams and the Atlantean epoch. See also sections on the Atlantean epoch as well as Christ Module 14.
It is understandeable that Rudolf Steiner did not go into black magic and evil more than limited mentions, this was not his mission and maybe also outside of 'the allowed' that he could disclose. As a result, focus in his teachings lies on Lucifer and Ahriman. However in comparison with Asuras and Sorat as their exponent, Lucifer and Ahriman are 'misguiding' Man left and right from the right and balanced path represented by the Christ (love). In comparison, black magicians and Asuras/Rakshasas are a head-on confrontational opposite, causing death of other living beings for the strengtenings of one's own selfish powers. These beings are already on another developmental trajectory, that of the creation of hierarchies of evil beings and the eight sphere.
As explained by the opposite characteristics of opposite planes, the 'wheel of planes' shows the eight sphere as opposite to budhi which is love.