Equipment:
Singing Spear
Runes of Warding
Runes of Witnessing
Spirit Stones
Mind War
Eldritch Storm
Doom
I plan on having him accompanied by a retinue of 4 warlocks. Three of which have the power 'Destructor', and the fourth has 'Enhance' as well as a Singing Spear.
Due to his lack of a ranged "Shooting Phase" ability, I decided to give him a Singing Spear so he can contribute to the short range combat with something better than his Shuriken Pistol.
Also, due to them providing a short range role, I decided to take Enhance to further better their chances of survival if charged. This ability gives them a +1 WS and +1 Initiative.
As far as El'toran, I like the idea of making him as dominating as possible in the realm of Psychic abilities. This is an individual who is not only most likely thousands of years old, but as a Farseer he is a kind of Exarch to the Warlocks. I gave him both sets of runes to boost his ability to cast, as well as to hinder his opponent's ability to cast. I have two damaging spells (both useful in completely different situations) and Doom, a "must have" in my book.
Eldar have a "common" strength and toughness value. I say common because I'm using a normal human as a basis for comparison. This can be a bother when facing enemies with toughnesses higher than 3. Marines, some Tyranids, Necrons, etc. The idea of a power which allows re-rolls to wound is amazing to me, and I intend on exploiting that as much as possible.
Spirit stones are another "must have" as they allow me to cast two spells per turn. That's a possible Doom AND a direct damage spell!
Mind War is good as a sniper-style power. The real benefit of this is that it can target an individual model. Want to get rid of that one Heavy Weapon, but have 9 of his companions basically in the way? Not with Mind War. The only thing to pay attention to here is that you have a Leadership roll-off with the target model. Choose wisely, or you'll be stuck with only a 50/50 chance of actually doing damage. A Farseer's Ld is 10, so make sure you know your enemy. Some things to remember: ALL Necrons have a Ld 10. Also, if fighting a Space Marine Army, if they have a Company Master on the field then ALL Space Marines use his Ld of 10 until he's dead. Imperial Guard officers have a lower Ld than most army commanders, ranging from 7 to 9. Exploit that. The only exceptions are the Commissars (Ld 10). Both Dark Eldar and Orks have officer/commander models with less than 10 Ld. Take them out. This attack ignores armour saves, even invulnerable ones! [EDIT:] I have been corrected. It does not ignore invulnerable saves ... but still ... ignoring armour saves is still cool. [/EDIT]
I took Eldritch Storm to balance out the Farseer's abilities. I had a great 'support' spell, a great 'one-target' spell, and now I have a great Large Blast marker spell. Sure the stats aren't great, but you're really not going to be using this on a squad of Space Marines ... you use this on Imperial Guard, or gaunts, or Orks. Armies where you need to score as many wounds as possible. Note that this spell also causes 'pinning,' so those cannon-fodder troop types generally are more susceptible to this as well. Another nice side-effect of Eldritch Storm is that it spins vehicles. This makes things interesting considering the possibility of a joint effort, in which you spin the vehicle around, then have your Fire Dragons (or whatever) hit it's sides/rear.
