Because he had an Achillies heel and we found it. we know next to nothing about the invading nascent souls.
Note that we knew nothing of Weeping Anvil's weakness when we began diplomacy with him for the legacies come Turn 13. Then Kleisthenes just knew exactly what to threaten him with when the talks came and the actions for creating the Droplet of Rust and Ruin became available on Turn 14, which we then executed in Turn 15.
We (the Clan) also know quite a few things about the invading Nascent Souls, even if we (the audience) don't; we know the identity of Ma Emperor from before he fell to the Blood Path and we know that Noble Knowledge Sect is supporting this invasion. We also know that Noble Knowledge Sect currently has three Nascent Souls: Divination Poison Lord, their Mid Nascent Soul (and Sect Leader), and two Early Nascent Souls that we know details about, but currently don't have their information as Occi hasn't written that down, because it hasn't been relevant yet. And we also know that them sending all their Nascent Souls to support this assault would be unreasonably foolhardy of them - because they're also at war with the Righteous Path, especially the Bear Enslavement Sect, as they prosecute the Poison Crushing Siege - so at least one Nascent Soul and possibly two of them will be in their own lands. This will almost certainly be Divination Poison Lord himself, because he is Sect Leader, and as Mid Nascent he is the greatest reserve power the Clan has, and risking his life in an invasion that has already gone wrong for them, for someone he doesn't particularly care for beyond this deal, would be risky. But we have a plan for if he's here as well, and it's called 'make him miserable enough to just fuck off and leave because this isn't a fight he has to commit to'.
This is a fight Ma Emperor has to commit to. He has sold away his Clan's lands and his people have nowhere to go. He has no Nascent Souls to feast on and can only break open Yuan's incredibly hardened defensive points to get any of the Yuan Cultivators, so his only available food source is his own Clan. He has no option but to attack, because delaying loses him everything he's fighting for.
(Blood Path's really fucked up like that.)
Incidentally the Nascent Soul List for this Region is available here, for people who don't know what I'm talking about.
Notably we also didn't know about the Spirit Severing Light Qi Trap that Old Cannibal tried to spring on us during the Cannibal War that ultimately ousted him from the Desert, nor did we know that he had given the Light Qi to the Jingshen when Jiao tried to spring it on us. Manuel dealt with it both times. Assuming that our lack of knowledge is Manuel's lack of knowledge is dangerously paranoid. This is the sort of thing you ask the GM about, not take for granted that we do not know.
Again - this assumes everything goes exactly as we hope it would and that we have perfect information on the invasion.
We don't - and there is no guarantee that nothing will go wrong or that we accounted for everything.
Getting the defensive treasures hedges our bets here, allowing us to both send two Nascents to Blood Oak to reap the benefits of your plan and defend the Yuan risk-free at the same time. Perhaps more importantly, the treasures are both going to be very useful long-term.
The Gravebone Panoply is a Spirit Severing defensive artifact which will be invaluable against Late Nascents once we inevitably clash with Old Cannibal and his vassals, our the main threats to continental domination that have both more and stronger Nascents than we do.
The Chrysocolla Paints is described as having allowed 13 Nascents and 24 000 Cores to hold off 3 Spirit Severing Cultivators without losses. We cannot field that large a force - but even in the short term, two Mid Nascents and three Early Nascents backed by two hundred Cores and led by Manuel with the Stone Spear, armored in the Gravebone Panoply would allow us to punch up at the Great Circle Nascent Souls just fine.
We know how many Nascent Souls they have. We know which Nascent Souls will be the ones deployed, and while we don't know how many they will deploy I will be
very surprised if they deploy more than one Mid (Ma Emperor) and two Early (the Noble Knowledge Sect Earlies).
We know the Stone Spear is a Law Creation Artifact capable of both Offense and Defense. It can stab the Sun. It can block things that should not be blocked. It can stab souls. It can block surprise Light Qi attacks. It is the single strongest artifact in the Region because it does everything a fight needs to short of choking the other dude and turning him into a slushie.
The Gravebone Panoply is a Spirit Severing Artifact and it is wasted on Manuel. It's more suited on Xinya or Kleisthenes if anything, to give her the ability to serve as taunt tank.
The Chrysocolla Paints were described as doing that for Nascent Souls back in the day, but let's keep in mind that was when the Sea wasn't dead and it hasn't been ten thousand years since it died. And as
@ReaderOfFate stated, we don't have that much left. This is a fight that doesn't need the Paints, so we should avoid buying it until we need it.
With that in mind, it's time to vote.
[X] Plan -ned Suppression
-
[X] Set Prices High - Hold onto the supplies for now in case the Pass cannot be reopened for half a century or more. This will cause more casualties now, but less in the long-term.
-
[X] Wait, and see what else might arise.
-[X] Fortifying (The Yuan Clan) - Spend Clan manpower and soldiers to build new fortifications against outside enemies. New Arrays, help train new cultivators in lesser Formations to defend their lands, and so on. Will also strengthen a vassal or ally if chosen, and increase relations with them.
Increases defenses in the chosen territory, ally, or vassal.
--[X] "It's a difficult thing to say, but the Archegetes may have invested overmuch in the gambits taking place in the Yuan clan. The Clan has often made due with less wealth, when the sweat of our
Optimatoi has served well enough to create great works and fortifications. We have enough forces deployed along the breadth of the Yuan, and enough resources invested in it. Let those who are already present dig in, and reshape our newest vassals land into a bulwark to rat out the temporary problem. And make a permanent reminder to the Region just who owns that land now. A declaration the Yuans invaders are unable to ignore, a perfect bait for their Nascent souls. A Monstrous Root Threshing Domain."
-[X] Manuel - Hunt An Enemy (Yuan Clan Invasion Nascents) - Why not? Hunt down enemies, see if you can kill someone. Usually used against an opposing Nascent Soul. Potentially
very dangerous.
--[X] "The
Archegetes remains our most powerful combatant by a wide margin, and even in a territory lacking in his typical preparations and schemes seeded throughout it, the Yuan Clan territories have their own defenses that they can inform us of, our own assets freshly deployed there to account for, and our own Legions to frustrate and inevitably bait out enemy Nascent Souls. Kill one, it may be insufficient. Kill many, it will definitely be enough. Catch them between a thousand anvils, and a singular hammer in the Archegetes and we can bring and end to this miserable affair, and not a moment too soon."
-[X] Kleisthenes - Open Diplomatic Relations (Blood Oak Sect)
--[X] "For too long have our new neighbors to the North gone ignored. I will be having Casia assist me in opening up formal relations with the Blood Oaks to the North. Regardless of what the ongoing situation is for the rest of the Region, they're direct neighbors with the Qiguai Clan, who we know are the direct target of the Gao Clan and Shattered Time Sect. If they intend to make moves there, I would rather we not act at cross purposes there.
-[X] Xinya - Accompany and Assist Manuel in Hunting Yuan Clan Invasion Nascent Souls.
--[X] "The
Archegetes can not be expected to perform his flawless preparations for combat as he normally could. However, our Third Elder possesses the necessary expertise to make up for it, as well as feed new sources of intelligence to the
Archegetes in order to better prepare and execute the necessary ambushes in order to truly end this final desperate gambit by the Ma Clan, once and for all.'
-[X] Casia - Offer Peace (Blood Oak Sect) - Casia's personal ability allows her to bring harmony between people and among them. Within the Clan she can calm vassals, outside of it she can calm relations, between the Clan and her target or between any two targets. If she were permitted to use this for twenty turns unobstructed she might end the current War, so it is more useful in repairing failing relations than trying to rebuild failed ones.
--[X] "With Casia's assistance I might be able to negotiate for terms and concessions that otherwise would be utterly unthinkable, especially in the absence of the
Archegetes peerless intelligence gathering capabilities to provide advantages for us to make use of. We will project Absolute Goodwill to them, and in doing so hopefully win the Blood Oaks over to our side, abandoning the Blood Path in its entirety. After that...there will only be two powers left in the Mountains, of which only one is capable of being harmful to us anymore."
-[X]
Forge a Wedding Ring (Major Purchase - 2 Purchases)
-[X]
Use 3 Shadow Key Points to Purchase the Earl's Insignia
-[X]
Use 2 Shadow Key Points to Purchase the Fortress-Mounts