Thank you guys! By the way, I started reading BotL, and think there is some good stuff in there! Maybe I missed it, but is there a thread with just the IAs for that universe? I saw Legion-specific and storyline discussion, but it seemed like it was a work-in-progress at this stage for most of the Legions? Also, is there a pre-Heresy background/history for BoTL?
Also, with respect to Twisthammer, I started thinking about tabletop applications, and got a few ideas. I don't feel completely comfortable coming up with TT rules, as I did not play enough of it to know if my suggested rules and stats are reasonable or garbage, but here are some ideas on the Primarchs.
Stefan Ignatiyev - in keeping with his nature as a quasi-mafia boss/spymaster/grey eminence with aristocratic pretense, he should have an average (for a Primarch) stat-line, though perhaps a close combat weapon emphasizing dueling with enemy characters (swordsmanship is an aristocratic pastime, and he could be above average swordsman - again, for a Primarch). His special abilities should center around bringing units from reserve, infiltrating units, and the like (a version of Heroic Intervention where he can bring a reserve unit onto the tabletop at will, and allow it to attack on the same turn). I would presume it would make him one of the lower point-cost Primarchs, and less effective combatants.
Kthuln - he is a close combat monster, and should be treated as one in terms of stat line and rules. As he loses Wounds, he should get stronger, and perhaps get additional rules such as FNP. This would represent the thin veneer of civilization slipping away to reveal outright savagery. Kthuln should be an all-around assault fighter, capable of slicing through any kind of enemy.
Zaeed - an average stat line, probably higher than average (for a Primarch) initiative, and a special ability centered around his "Storm Bringer" trait (either treated as a psychic long-range attack, a debuff for enemy troops, an ability to give allied troops a cover save or to infiltrate them). He should be more of a force multiplier than a fighter expected to carry the army on his back.
Echelon - uniquely amongst the Primarchs, Echelon should be a unit of 3-5 models, one of which is designated as Echelon Prime. The non-Prime models would all have strong stat line (but below a Primarch), something akin to better versions of Dreadnoughts. The Prime model should have a stat line of a lower-end Primarch, with a choice of advanced technological wargear intended to kill from distance rather than for close combat. The non-Prime models can be detached from the unit and attached to other Steel Wardens units as Independent Characters with buffs for the units they join. If the Prime model is destroyed, another non-Prime Echelon model can be designated as Echelon Prime (its stat line would increase, but its wargear stays the same). This should represent Echelon's multiple bodies and ability to transfer command between them. Naturally, this would make him one of the most expensive characters, points-wise.
Ashur - second highest Initiative amongst the Primarchs, Combat Drugs rule (FNP variant), one of the better close combat Primarchs. Can take a combat bike, which should give him improved Toughness. Should be one of the better combat-oriented Primarchs on the tabletop, representing that he is a powerful and unpredictable fighter, but perhaps less of a general and more of a gang leader in mentality.
Iskanderos - should be pretty well-rounded with no particular weaknesses, and a number of buffs for the troops to represent his generalship. I see him as more of a "baseline" Primarch, at least before his fall to Chaos.
Mohktal - THE psychic Primarch, who is also a close combat monster with increased Strength and Initiative (think Eastern martial arts as the cause, and as an application of many of his psychic powers). His psychic abilities should be centered more on buffing himself and his men, as opposed on ranged attacks and the like.
Nihlus - slightly above average in close combat, but has psychic powers geared towards offense and debuffing enemies. Enemies within 6" suffer from -1 Strength or -1 Initiative (due to noxious smell and Nihlus' terrifying visage). May cause Fear. He is more of a fighter than a force multiplier.
Nyxos - if Corax and Kurze had a bastard love child, and then let Mortarion raise him, he would be Nyxos. Anti-psychic measures, plus a close combat monster with stealth-themed army buffs. Causes Fear.
Gideon - another well-rounded Primarch, with buffs to nearby allies, and perhaps abilities centered around giving Astartes units unique abilities. Not too different from Iskanderos, but probably more ranged centered than close combat.
Baelic - should be all about close combat, but gets bonuses when fighting characters, monstrous creatures, and the like (worthy opponents, and all that). Not much of an army buff character, but a fairly straightforward fighter/duelist. Might have extra attacks due to his two swords. Baelic should be essentially a budget version of Kthuln, but geared to fighting characters, monsters, and the like, where he excels.
Rogr Hemri - he should have a rather average or even slightly below-average stat line (he is a politician and a ruler, not a front-line fighter), but most of his abilities should center on buffing friendly units to represent his skills in propaganda, spinning the story his way, and getting others to go along. His added value is by allowing the player to bring greater numbers to tabletop than normally possible, or perhaps through enabling some "cannon fodder" units to be taken at decreased cost. By himself, Hemri should not be great on TT, but he should be a decent, if budget-priced, force multiplier for an army built around numerical superiority.
Dyal Rulf - as one of the more secretive, scientifically minded Primarchs, Rulf would have an average or even a below average stat line, but with abilities to compensate. He would give his army Preferred Enemy (or equivalent) to represent studying the enemy's weak points, and perhaps extra movement during one of the phases (to represent his preference for rapid, coordinated assaults). Rulf should be less about fighting in person (though he would be at least somewhat competent at it, even if not great), and more about exploiting weak points of the enemy army through Preferred Enemy, debuffs, preventing the enemy from bringing Reserves into play, and making the other player reroll the dice.
Angelus - he gets Wings by default, which essentially turns him into a Flying Monstrous Creature. In addition, he should be in the upper quartile of Primarchs with respect to close combat, and a high Mastery level psyker. His psychic powers should be centered on ranged Witchfire attacks, and divination/clairvoyance (rerolling unfavorable dice results, making the enemy roll for reserves, etc). This should come with a few flaws, as could be expected from a guy who constantly hears voices in his head - he might have to take constant Leadership checks, where on the roll of 1 he would be essentially paralyzed for the duration of a turn, to represent him being extremely volatile. I presume he would be one of the higher point cost Primarchs.
Griven Kall - archaeotech and xenotech are the words of the day. Griven Kall should be an above-average fighter (though not on the level of Kthuln or Baelic), but he should be loaded to the gills with wargear, unique devices, and plasma weaponry. He should have a decent amount of buffs to the units in his army, and make non-Astartes units fight considerably better (he is considered a hero of the Imperium, after all, thanks to his anti-xeno stance). He should also have Preferred Enemy (Eldar) due to his adventures in Commoragh... I doubt he would make a distinction between regular and Dark Eldar.
Leto - his stat line should be the definition of average for a Primarch, not flashy but effective. His abilities should have more to do with him arriving in the right spot, at the right time, and with the right wargear. As one of the smartest Primarchs, he would have the ability to change one or two of his special rules during the game (adapting to the battlefield situation), though once the change(s) is made, it is permanent for the rest of the game. Leto should give a decent amount of bonuses to allied units, and should uncover some additional unit synergies (perhaps giving bonuses to unit A as long as unit B is also on the table, and vice versa). He should be one of the better force multiplier Primarchs, if not the best or the most expensive TT option.
Andrieu Ulliann - Andrieu is the "random" Primarch, meaning that before the game, the player should roll on the table to pick one (or more) special rules. Those rules would apply through the rest of the game, and would represent Andrieu's tactical unpredictability (and his approach to war as a talented dilettante rather than as a true general, which may lead to strange choices). His other rules would include some sort of unit buff due to inspirational leadership, and ability for certain Legion Elites to roll for an application of a special rule pre-game. He would be one of the mid-cost Primarchs, as he has potential to be extremely powerful with some luck, but can also be a point sink with little return if the rolls do not go your way.
Marvus - a spymaster/taskmaster/resident psycho (though he hides it very well) with a reputation for dirty fighting, which implies that he should have access to WMD style wargear. He should not be the best hand-to-hand fighter, and in fact be fairly average at that, but he should be a decent all-around support/force multiplier character. Marvus can be one of the lower point cost characters, and more of a budget Primarch option.
Maikhaira - the highest initiative among the Primarchs, combined with one of the better close combat stat lines/war gear/rules combinations. He should be fast, good in close combat, and probably equipped with a jump pack. He should have a Larai-i-Moha rule, which is essentially a battle trance he enters when sufficiently wounded. At that time, he would gain FNP or similar, Preferred Enemy, and extra movement, at the cost of being forced to move to the nearest enemy unit and attack it in close combat. In addition, he should be able to buff a single unit of Iron Locust elites to give them a significant boost, or give all Iron Locust units within 12" of him an Initiative boost (thanks to the quasi-"hive mind" connection). To further the "hive mind" connection, he should be able to allocate some of his wounds to an allied unit, though this ability needs to be toned down so that it does not become too powerful. I would imagine him being a rather high-point cost character.
Corwin - an above-average (though not exceptional) WS and number of Attacks, though rather average in other respects. His strength is in giving his units a plethora of special abilities (either Eternal Warrior, FNP, or something similar to represent their extreme levels of devotion on top of their existing knightly honor code). If he is about to lose his last wound, he can execute a special move up to 6" to avoid harm, and to negate the attacks targeted against him that turn. This ability can only be used once per game, though if he cannot make a legal move, he would be taken off the table. His other special abilities should allow an Angel Kings army to take Knight walkers at reduced point cost for a Heavy Support slot (or equivalent).
What do you folks think?