· Bane of Empires
This is what Codex: Dark Eldar says on the matter:
In regards to the Haemonculi Pacts:Codex: Dark Eldar said:Whereas the Eldar of the Craftworlds learned to deny Slaanesh's hold upon them using mystical spirit stones and infinity circuits, the Eldar of the webway became exceptionally good at ensuring that lesser beings suffer in their stead...
Provided they steeped themselves in the most evil and decadent acts, the Eldar of the webway found that the curse of Slaanesh could be abated. The agony of others nourished their withered souls and kept them vital and strong, filling their frames with unnatural energies. Assuming they could feed regularly enough, the Eldar of the webway became physically immune to the passage of time. So it was that the Dark Eldar were born, a race of sadistic murderers who feed upon the anguish of others in order to prevent the slow death of their immortal souls.
Codex: Dark Eldar said:Most Dark Eldar warriors... will at some point enter into a terrible pact with the Haemonculi... The pact states that the Haemonculi will regenerate the warrior's body should he die, and in exchange, the seeker will leave the Haemonculi a permanent portion of his soul. Even a corpse that has been all but destroyed... can be restored to its former glory. Provided this process is enacted within a day or so of the warrior's demise, and his will is strong enough that some of his spirit still resonates within his remains, his animus will slowly regenerate along with his physical form.
As per the above quote, it seems to be the case that the regenerated Eldar is not a clone, but the same Eldar - simply regenerated. Leaving a portion of the Eldar's soul with the Haemonculi prevents Slaanesh from consuming the Eldar in question. I imagine such a process would leave the regenerated Eldar drained and in desperate need to 'feed' his soul with the suffering of others.I'm not sure what actually happens to the rest of them, the part that actually dies. I had considered that Slaanesh does indeed claim them, and the regenerated clone is simply that; a clone.
Unless it is by some method that the haemonculus guarded part of their soul is able to draw the rest of it back before Slaanesh takes it. But I'm not really sure, the details are left pretty vague.