Given Yzarc's slightly ominous post, can anyone see any weaknesses in this plan or things the Chaos Army/its sponsors can exploit or counter?
The description of it as a gambit pile up makes me wonder if there's something they can do we haven't anticipated.
We've previously revealed our ability to call storms and our power armour, and Lorgar's Telepathy. Is there anything people can think that can be turned against us?
They could use the start of the sandstorm as a signal that we're coming and start preparing traps or summon daemons that then hide somehow. Fan doesn't have supernatural senses. Lorgar, however, does, so we may want him to accompany Fan when he runs ahead of the main body of the army. Lorgar can then look for any hidden threats that are too great a risk so we can either account for them or decide to try again later. If we throw sandstorms at them a few times without attacking they're likely to stop making as thorough preparations, as they're probably expensive.
In terms of the power armour, Thalassa used the Mechanicum rites on our gear to protect it from scrap code, but it may still be a threat.
For the Telepathy, they may try to have someone ready to telepathically duel Lorgar if he tries to use it on them again, which between True Faith and Mind Shields would probably be a severe error on their part. They may also have someone waiting to try to jam him. I'm not sure what we can do about that apart from hope Lorgar's strong enough to prevail.
In terms of their own gambits, the main one I can think of is them having prepared a sorcerous ritual as a giant trap. If that's the case then we may want Lorgar/Dharok on alert to use True Faith countermagic on it. The other big one I see is them having daemonic allies suddenly manifest on top of us. The best answer I can see to that is to use True Faith to ward them off. In some 40K sources people with sufficient Faith can bless their allies weapons to be able to hurt daemons. Maybe one for
@Yzarc, would Dharok/Lorgar be able to do this, perhaps with a True Faith 9 miracle? If so, we could have them ready for this.
For the thread, one thing we're not doing is using Enuncia. Do we want to take the risk of hitting enemies with it, particularly and daemons that are summoned?
Any one see anything else we need to take into account?
As a before action review; thinking about what tech we're missing that I'd have like to have had when planning this that I thought I couldn't justify our people having.
Power armour. Versions that don't require a Black Carapace exist, even if they're usually harder to interface with and control. If regular space marines without an awakened mythos can receive mutations that aren't derived from their Primarch's Mythos (as Chaos Space Marines suggest), then the option to make our warriors into were-space marines may still be on the table. This would mean our warriors look less like mutants and should also help them live more normal lives when not in combat, which would make the transformation much more palatable.
Jet packs that integrate with Power Armour. Fan may be able to fly at his normal ground movement pace, but jet packs would be much faster, and the rest of the circle can't fly*.
Perhaps stretching the definition of equipment, but, grav bikes would be absurdly better than regular bikes in the desert, and that's ignoring their ability to carry heavy weapons. This is on both tactical and strategic levels, as imperial jet bikes can reach just sub-sonic speeds. This makes hit and run attacks much easier but also means a force mounted on them can travel around the continent vastly faster than a regular army, which is an enormous force multipler.
Virus grenades. Potentially comically effective against a mostly medieval tech army, even if some are blessed by Nurgle most won't be. Also, relatively safe to deploy in a desert.
Other weapons that require ammunition. Given our almost completely absent industrial base, things like missile launchers with plasma munitions, while likely effective, didn't seem a good idea. As would plasma grenades to throw with superhuman strength at incoming chaos warriors. Or man-portable mortars firing plasma rounds indirectly over a ridge line into the Chaos army. If we do have any of this we should save it for a potential final battle at our home.
Remote controlled aurveillance drones. I'd be more confident about our plan if we could survey the land and know what route the Chaos Army is taking and what rhey're doing before planning where to send the sandstorm and where to attack them. We couldn't deploy drones in the sandstorm; but before then they'd be very useful.
Psi-tech. Force weapons or psi-boosters for Lorgar and Dharok.
Other enchanted weapons and armour**. I'm not sure if they exist, but if the Sorcery path of Enchantment is available then this gear might be a better counter for any esoteric defences or attacks the Chaos Warriors have.
Augmentations. We should get on with developing our genetor augmentation packages, as this is a slow burner. If we get a few regular space marines I've realised that we may want to run a parallel mutation reverse engineering project on them to try to derive non-supernatural upgrades to the basic space marine package. We know this is possible, there's a 'superior' space marine who appears to be a surviving Thunder Warrior that had geneseed implanted in the Heresy Era, as well as the Primaris marines of a potential far future. There are other forms of technological augmentation we should consider as well. For example, it's canon that there are Skitarii with super-tech like quantum bioware cerebral implants. I'm not sure what combination of Savant specialties would be required for Thalassa to duplicate those. There's also bionics, which I'm a bit sceptical about deploying widely, given the risks of Scrap Code.
Other things that would have been helpful include granting/teaching Lorgar and Dharok Maelstrom Sorcery so they can assist with rituals, and closing the Wound so that we could ask for the spirits' assistance with Sorcery. A stockpile of exotic reagents wouldn't have hurt either.
* long term, for Dharok and Lorgar, I wonder if it would be possible to combine the Wings mutation with the Hidden Power merit, fluffed as Diablo angel style wings of light that can be manifested and dismissed at will. Seems cooler than jet packs. It also seems in line with a combination of Light and Celestial Lores and the fact that the Lores are quasi-psyker manifestations of True Faith. Might not be though.
** Long long term it would be nice to develop Path of the Arbiter Style and have a core of Enlightened space marine elites who can manifest artifacts from their own essence. I suspect this is a very long road though…