It is not generally known that the Tamil (South Indian) Siddha (perfected master) saint and poet Swami Ramalingam, also known as Vallalar, was the one who initiated the work of Supramentalization that was continued by Sri Aurobindo and the Mother. Of course, even Swami Ramalingam was carrying on the work of earlier Adepts like Tirumular and Christ, who in turn were carrying on the work of still earlier adepts, each progressing further in the Goal (and also reincarnating boddhisattva style to continue the work).
Ramalingam was an extraordinary figure, who as well as attaining great states of consciousness, taught a sentientist philosophy of compassion to all beings, very much like Ramana Maharshi, and instituted the providing of free food to the poor.
He attained a Supramental state of deathless triple body; the siddha or perfected physical (gross) body, the subtle or mantric body, and the jnana or knowledge body. Finally, he dissolved his outer form (the equivalent of the Tibetan "Rainbow Body" in order to enetrr into universal existence and continue the work of Supramentalization that was then taken up by Sri Aurobindo and the Mother.
I have only just begun to explore this subject, but what it reveals is the interrelationship between the Tamil Siddhas, and perhaps other Siddhas as well, such as the Natha and Kriya Yoga traditions and Tantra in general, and the supramental yoga of Sri Aurobindo and the Mother. Quite likely also the Christ avatar (represented both by the historical Jesus and by Eastern subtle realm figures like Kwan Yin), and other influences can be found as well.
Wikipedia page that does not cover these themes but gives some hagiographic background,
Ramalinga Org very good webpage that also explains relationship with Sri Aurobindo and the Mother
Auro-Ma-Ramalingam - extensive website that further explores these themes regarding parallels with the Aurobindonian Supramental Body, based on the writings and research of T.R. Thulasiram. Contains some very inspiring material, although I disagree with a few of the interpretations, use your own insight to distinguish them. I notice that Google has a warning that "this site may harm your computer" but I have never had any problems there, so I leave it to your discretion.