Editing Warhammer 40,000/7th Edition Tactics/Chaos Space Marines (section)

===Thousand Sons Grand Coven Detachment (Wrath of Magnus/Traitor Legions)===
The Thousand Sons Grand Coven is is meant to buff Rubric units/Psykers to be more viable, though the actual results are...questionable. The formation bonuses are:
*'''Lord of Fallen Prospero:''' ::Your Warlord gets to re-roll his Warlord Trait if he rolls on the Tzeentch Warlord Table. This table is arguably a lot better than the vanilla Chaos one, so may be worth considering.
*'''Masters of Arcane Knowledge:''' All Psykers in the detachment may cast an additional power beyond their Mastery Level. The most immediate ways to use this are lucking out and getting the Warlord Trait that lets you know an additional Psyker Power, or using Ahriman or Magnus, the former due to knowing more powers than his Mastery Level and the latter due to the Black Staff. Worst comes to worst, this also lets your Aspiring Sorcerers pop Force to improve their unit's invulnerable save while still being able to cast their one Tzeentch power they rolled or the Primaris. Additionally, all Psykers in the detachment may re-roll their result on Perils of the Warp. This one matters more, as extra insurance against accidentally frying your expensive Sorcerers is always nice.
**'''Favoured of Tzeentch:''' If you take the maximum number of units allowed for a formation (usually a commander + 9 units, because Tzeentch), every model in that formation may reroll all saving throws of 1. While for many formations this is excessively expensive, for others it allows for incredible durability.

====Command (0-4)====
*'''Rehati War Sect:''' Magnus the Red plus 3-9 ML3 units of either Tzeentch Daemon Princes or Exalted Sorcerers. The models in this formation ignore Line of Sight for casting powers. In addition, all models within 18" of Magnus manifest on a 3+. This formation tends to find more use in Chaos Daemon armies as a way to get Magnus into their army without actually having to include Thousand Sons.
**One of Traitor Legions' only Bikestar Formations.
*'''Ahriman's Exiles:''' Ahriman plus 3-9 Exalted Sorcerers. All models within 18" of Ahriman manifest on 3+.
**Another of Traitor Legions' only Bikestar Formations.
*'''Lord of the Legion:''' Magnus the Red, Ahriman, or a Sorcerer, Exalted Sorcerer, or Daemon Prince of Tzeentch.

====Core (1+)====
*'''War Cabal:''' Ahriman, a Daemon Prince of Tzeentch, a Sorcerer, or an Exalted Sorcerer with 1-3 more Sorcerers/Exalted ones lead 1-3 units of Rubric Marines and 1-3 units of Scarab Occult Terminators. Whenever a Psyker from this formation manifests a power, that Psyker (and the unit it's part of, should it be from this Formation) may reroll all 1s to-hit for the remainder of the turn. This formation is the "cheap" core of the two, and is probably what players will take just so they can run 3 units of Terminators with rerollable 2+ armor saves...
** '''Summary:''' This formation is probably the best core T-sons could ask for. rerolling 1s to hit is extremely useful for such a shooty army, and because literally every unit in this formation has a sorcerer leading it, you can consistently get rerollable 1's to hit every turn just by activating the sorcerers force weapons. Combine that with the bonus spell every sorcerer can cast from the detachment buffs, and you will be unleashing a LOT of DAKKA in the psychic & shooting phases to cover any shortcomings that may occur in close combat.
*'''Sekhmet Conclave:''' A sorcerer(can be exalted or Ahriman) or a Daemon Prince(can be Magnus), plus 3-9 units of SO Terminators. Any unit from this formation within 6" of 2+ of other units from this formation gains +1 Toughness (Mortarion is Jealous). This is what you want if you like Terminators, like being nearly impossible to kill, are sick of regular Rubrics being overcosted crap, or just don't want to paint very many models. You won't get the rerollable 2+ armor saves with this unless you take nine units of 5 terminators each plus an HQ, though, which is not going to happen in games under 2500 points.
**'''Quick Note:''' While it's true that this formation is extremely expensive, especially when trying to get the blessing of Tzeentch, it's not always needed, thanks to +1 toughness. Also, the toughness buff is applied to Magnus when in range of the termie honor guard which makes him TOUGHNESS 8 meaning he is '''COMPLETELY IMMUNE TO BOLTER FIRE''' AND strength 6 weapons only wound him on 6s, so suck it space elfs. Splinter rifles still wound him on 4+.

====Auxiliary (1+)====
*'''War Coven:''' 1 Tzeentch Daemon Prince, ES, or Sorcerer leads 3-9 more Sorcerers/Exalted Sorcerers. Pick one BRB Discipline at the start of the game, and all Sorcerers from this formation manifest Warp Charge for that Discipline on a 3+. This is basically your Librarius Conclave formation.
**Are you a bad enough dude to run the Terminator Tzeentchstar? Take ten regular Sorcerers in Terminator armor and enjoy your ten man invisible 4+ FNP  rerollable 2+/3++ teleporting witchfire spamming deathstar with two wounds apiece. Be sure to include the Seer's Bane and the Astral Grimoire to go fast and dominate in melee too. Warning: you won't have any points left over for actual units if you do this. (Amazingly unfriendly in 1750pts. You will utterly dominate the game, short of truly broken enemies, then lose because of objectives)
**One of Traitor Legions' only Bikestar Formations.

*'''Tzaangor Warherd:''' 1 Exalted Sorcerer/Sorcerer leads 3 units of Tzaangors plus an optional 6 more units of Tzaangors or the unnameable beasts. The entire formation gains Fleet, the Tzaangors may run and charge in the same turn, and should they roll a 9 or more for Charge distance, they gain +1 Strength and Initiative. Not bad at all. 

*'''Daemon Engines:''' Defiler, Forgefiend, Heldrake, Helbrute, Maulerfiend. Pick one. Not actually a formation. this is the closest thing to a spawn formation that T Sons get so if you want to go all in on your core choice, take a bare bones helbrute, maulerfiend or predator tank.

*'''Legion Armory:''' Grab either a Chaos Land Raider, or a unit of Predators, or Vindicators. Remember you can squadron if you don't want to give up first blood, but a Land Raider may work to cart around the expensive asses of the Scarab Occult Terminators.