As an auxiliary to the ongoing thread about the size of the eldar race, I thought I would start a new thread regarding the combined Saim-Hann and Biel-Tan attack on the Imperial planet of Gnosis. *This attack is described in Planetstrike, pages 61-62, and while much operational detail is missing, a considerable amount of interest can be gleaned from what we do have. *I'm starting this as a separate thread because I think it has potential to range beyond the plausible minimum size of the eldar, and also in case it ends up being a long tangent.

The eldar ordered the Imperial colonists (present for some 1,200 years) to evacuate the planet within a day. *Believing that the eldar had only a diplomatic delegation on station (and in view of the obvious impossibility of evacuating a planet within 24 hours), the Imperial governor told them to sod off. *The eldar attacked. *We are not told what their objective was, but given their demand, I think it is reasonable to assume that their objective was to kill the human population of the world.

If this be so, their method of going about it is most instructive.

Gnosis had a primary industrial sector that comprised five hives: Judica, Ulyx, Cholerix, Toxinhive, and Nightspire Hive. *All of these were on the same continent, Gnosis Prime. *These are the only hives the eldar would attack, so it is possible they comprised the planet's sole "industrial" centers (we aren't told what is meant by "industrial"). *They were defended to the north by a strong series of bastions and defense lines, to the west by rugged mountains, to the east by an ocean, and to the south by the Auros River, which separated Gnosis Prime from the next continent south, Gnosis Parallel. *Unbeknownst to the Imperials, a number of wraithgates opened up near the Gnosis Prime hives. *At the time of the invasion Gnosis hosted an Imperial Guard garrison consisting of Valhallan and Cadian regiments of unknown number and composition. *In addition to this, we may presume that each hive had a PDF garrison, again of unknown number and composition, as Planetstrike speaks of "hive" garrisons participating in the campaign.

Nightspire Hive was eliminated by surrounding it with a force field and opening a portal to Commoragh in its heart. *Cut off from reinforcements and with dark eldar raiders pouring straight into the heart of the hive, Nightspire Hive would play no further part in the campaign. *We are not told how the force field was erected, nor how the eldar forces opened a portal to Commoragh within - though it is interesting to note that the Saim-Hann and Biel-Tan forces were willing to use dark eldar "allies" in this way.

The attack on Toxinhive began with Saim-Hann forces bypassing the northern defense lines from the ocean, riding east to west in the defense lines' rears. *The garrisons of these defense lines (implied to be Imperial Guard) left their positions to engage the Saim-Hann forces, but owing to the eldar's superior overland speed, were unable to bring them to battle before they reached Toxinhive. *The Toxinhive garrison was lured to the northeast of the hive, whereupon two "armies" of Biel-Tan aspect warriors exited the Webway east and south of the hive and carved through the concentrated hive garrison at close quarters.

Hive Ulyx, implied to be the planetary governor's seat (his name is Ulyx, and he has named his prize northern fortifications the "Ulyxis Lines" is attacked from the ocean by a Saim-Hann force. *Ulyx sends "his" "armies" (possibly the aforesaid Guard regiments, who may have been detained for garrison duty by the planetary governor) to give battle on the plain east of Ulyx. *The Saim-Hann forces engage long enough to allow the forces attacking Toxinhive to take Ulyx in the rear, then break off and attack Cholerix.

Cholerix actually defeats the eldar attack due to the fact that the hive populace storms the armory in order to join the Guard in its defense. *This is particularly interesting as it implies that the other hive populations did not do so; this fact also notes that Cholerix was defended by the Imperial Guard, whom we may generally assume to be the highest quality Imperial troops engaged in the campaign. *The attack on Cholerix may also have faltered due to impending Imperial reinforcements from Hive Megaera. *The Biel-Tan force that materialized south of Cholerix never engaged the hive, instead diverting to halt the armored columns from Hive Megaera that were crossing the Auros River. *The Biel-Tan forces appear to have engaged the Megaeran armor just in time, as the Auros Bridge was actually collapsed during the battle. *After multiple attacks are repulsed, the Saim-Hann force that lured out Ulyx's defenders disengage again to strike Ulyx from the south, thus catching the returning armies in the rear.

Hive Judica's garrison is lured north as it attempts to flank the Saim-Hann force leaving Cholerix to re-attack Ulyx. *With the garrison gone, two Biel-Tan forces of aspect warriors materialize south of the hive and take it. *One of these two forces splits to halt the Valhallan 121st Infantry from crossing the Auros River at the Thurian Bridge. *They deploy an Avatar of Khaine against the Valhallans, which is blasted by massed battle cannon fire and whose flaming corpse sets the polluted river ablaze.

With four of the five industrial centers "in flames," and Imperial reinforcements converging on Gnosis Prime from across the globe, the eldar forces withdraw completely. *"Millions" of Imperial citizens lay dead at the end of the campaign. *Planetstrike notes, in closing, "With the industrial lifeblood of the planet cut off, the world of Gnosis was doomed to a slow and painful death." *We aren't told exactly how - whether the loss of those industrial centers meant the planet was no longer worth receiving offworld supplies, or they made the atmosphere breathable, or whatever, but evidently, the damage was done.

A few things about this campaign stand out to me.

One is that eldar aspect warriors kick *** in close quarters. *Even against the massed garrison of Toxinhive, the Biel-Tan aspect warriors "rule ascendant." *I would expect aspect warriors to be no less effective than space marines in such circumstances, but it's nice to see some confirmation.

Two is that the eldar forces almost never actually fight, and they certainly never fight fair. *The Saim-Hann forces feint north of Toxinhive, east of Ulyx and north of Judica, but only attack in earnest at Cholerix - and then only when their aspect warrior support is diverted to stop what was evidently an emergent breakthrough. *Even at Cholerix, when their attacks are repulsed, some Saim-Hann forces break off to lure more Imperials out of position. *In turn, the Biel-Tan aspect warriors never engaged hive forces without weakening them some way - at Toxinhive, by cramming them into a portion of the hive; at Ulyx and Judica by striking only after Saim-Hann forces had lured the hive garrison away. *Only to hold off enemy reinforcements did Biel-Tan fight full-strength Imperial units, and then they had the benefit of defending bridges.

Three is that although this campaign was waged across a continent and five hives, the damage done must have been quite small. *Despite the fact that the bulk of the actual fighting took place in hive cities, only "millions" of Imperials died. *The actual eldar objective seems to have been destroying Imperial industry, which evidently could not be rebuilt (not uncommon in the Imperium). *The strategic goal was to kill all humans, but the operational goal was simply to blow up some machinery. *Given how many people live in a hive city and that the hive fighting consisted of aspect warriors against weakened garrisons, it seems likely that if the aspect warriors had been butchering people deliberately the casualties would have been higher.

As for the size of the forces involved, I think we can go as low as hundreds of thousands of aspect warriors - that is to say, a kill ratio in the neighborhood of 10:1. *Tens of thousands would mean 100:1 kill ratios, which even for aspect warriors fighting in highly favorable conditions pushes the bounds of my disbelief (I wouldn't accept 100:1 kill ratios from space marines either). *The Saim-Hann forces presumably were smaller, since they consisted of jetbikes and grav-tanks, and armored forces always have lower headcounts than infantry. *I think we can accept, as a lower boundary, tens of thousands of Saim-Hann troops.

Thoughts? *Other insights?