Looking at the strategies of both sides for ending a desolation

[agrabes]

Definitely an interesting topic.  Here are my thoughts as to why Desolations end.  I think it changed over time as both sides learned more strategy and tactics.

 

Early Desolations:

In the early years, things were probably mostly fought straight up.  The Heralds were still sane and idealistic.  The Fused were also still fully sane and likely thought there was a chance they could win in a straight up battle.  Most likely, the Heralds did eliminate all or most of the fused and then voluntarily returned to Braize.  So, early on it probably was fought like the default assumption - the Desolation was ended voluntarily by the Heralds after they had killed all known Fused.  The "time limit" existed at this time, but never came into play as a war ender.  I think this probably lasted for the first 2-3 desolations.

Middle Desolations:

In the middle years, the Heralds were losing their idealism and sanity.  For them, it was becoming a more desperate struggle to balance saving their people, upholding their oaths, and saving themselves from torture.  This is when they started dreading ending the desolations.  For the side of the Fused, I think this is when they started realizing they could not win a straight up fight with the Heralds and Radiants.  They started the "total war" tactics described by the OP.  The Fused started losing their sanity as well.  My suggestion of how the desolations ended at this time and how the time limit came into play is that the time limit starts when the Fused stop attacking humans.  So - some Fused who are insane or lost to bloodlust would charge in and fight the Heralds in pitched battle.  Once these were defeated, the Heralds returned to Braize.  Other Fused, who stayed sane and were more strategic would stay behind and cause havoc after the Heralds leave.  However, this strategy is only partly effective - by this time the Knights Radiant are the main fighting force of Team Honor.  The Radiants still defeat these "left behind" Fused who are less effective since not all of them are around.

Late Desolations:

In the late years, the Heralds are all insane except Taln and have basically become psychological casualties of war.  They keep fighting out of obligation and habit, but in general are no longer fighting in a strategic way.  They are just worried about self preservation, except Taln.  The Fused are mostly insane as well at this point, consumed by bloodlust and rage.  They've learned that their "stay behind" tactics are not effective.  If all of them were sane, they could try a "mass stay behind" tactic where they all stop attacking to trigger the time limit on the Heralds, but too many are insane to make that tactic work.  As time goes on, the Fused are more and more likely to just throw themselves into battle blindly at the first opportunity because they can't think strategically anymore.  The ones who do think strategically have less and less ability to keep the others in check.  The Fused continue their total war/genocidal war strategy.  If you are Odium you are thinking things are going well.  It's a war of attrition - the side of Honor is losing.  The Radiants are holding strong, but the humans in general have been knocked back into the Stone Age and the Heralds are going insane.  Your own Fused are also going insane and most are no longer capable of good military tactics, but this still works for you.  If they just go out in massive wave attacks, they'll kill more and more humans.  They die, go back to Braize, torture the Heralds for a few years, then come back and kill more humans a few years later.  By the time of the last desolation, they've almost succeeded.  We know from Taln, the humans were basically cavemen during the last Desolation.  The insane, bloodlust filled Fused likely try to go for the throat and try a massive pitched battle where they think they will win it all.  They know that even if they lose, they'll get another shot in a few years when the Heralds break again.  Due to the luck of battle, only Taln dies.  This results in the long pause between desolations, wrecking Odium's strategy and resetting everything.

 

So, TL;DR - Desolation ending timer starts when the Fused stop attacking Humans.  Most Fused are too insane and filled with bloodlust by the time they realize this to make effective use of the strategy and the Knights Radiant are strong enough to defeat the ones that do with the help of the Heralds.  Odium's plan is to win a war of attrition by grinding humans down and he almost succeeds.  The plan only fails due to none of the weak Heralds being sent back to Braize the last time.  If other Heralds had gone back, one of them would have broken within a few years and kept the cycle going until the humans were destroyed.  Even the Knights Radiant would have been ground to dust if they had no support from the general population.

[+Oltux72]

8 hours ago, Master Silver said:

I think Odium must have convinced Honor (Tanavast) to have a contest over the Roshar system, agreeing to remain bound in the system until he won.

The problem with this option is that Odium wants to get out. How else would you explain his conversation with Dalinar? If he changed his mind, why did his future sight not warn him?

8 hours ago, Master Silver said:

Odium knew he couldn't win in a direct confrontation 1 vs 2, so he used honor against Honor, knowing Honor would want to protect the other shards, some of whom were likely his friends.

That in turn raises the question why the Heralds agreed. This options mean that they either willingly consigned their descendant to a cycle of genocidal wars or Honor tricked them. Why and how?

 

[SirNoSell]

8 minutes ago, Oltux72 said:

The problem with this option is that Odium wants to get out. How else would you explain his conversation with Dalinar? If he changed his mind, why did his future sight not warn him?

Future Sight is inconsistent. Odium's admitted that he can't always see what will happen.

9 minutes ago, Oltux72 said:

That in turn raises the question why the Heralds agreed. This options mean that they either willingly consigned their descendant to a cycle of genocidal wars or Honor tricked them. Why and how?

That's stuff we'll have to find out, there's so much we don't know. The Stormfather theorised that they didn't know what they were getting into, so perhaps Honor might have left out the part of eternal torment at the hands of the ones they were imprisoning.

[Master Silver]

Also, Honor did not realize that humans could break their oaths, unlike Shards and Spren. This was untested at the time. And likely when this contest began both Singers and   and humans were loyal to Honor. The Singers feeling betrayed in turn abandoned Honor, after the humans started to expand. At which point Odium promised to give the Singers the power to defeat the humans. This in turn led Honor and the Heralds to make the Oath Pact. After realizing it wasn't a permanent solution, the spren of Honor and Cultivation began bonding humans, which eventually led to the Knights Radiant being founded. A continual escalation of force with Shards putting more and more of their power into the contest. Odium however doesn't really need to pour power into rebuilding after a conflict. Leading him to conserve more power. He eventually sees and opening and kills Honor. 

[+Oltux72]

2 hours ago, Master Silver said:

Also, Honor did not realize that humans could break their oaths, unlike Shards and Spren.

Tanavast was human. He remembered not holding a Shard. Either carrying a Shard does something very bad to one's memory, or this is a dubious assumption.

 

[Master Silver]

@Oltux72 I don't remember who, likely the Storm Father, but someone mentions that men unlike spren and shards can break their oaths. To me this indicates that Tanavast didn't foresee that problem and he thought the oath pact was a permanent solution. And being a Shard does warp their minds, as Odium indicated

[+Oltux72]

41 minutes ago, Master Silver said:

@Oltux72 I don't remember who, likely the Storm Father, but someone mentions that men unlike spren and shards can break their oaths. To me this indicates that Tanavast didn't foresee that problem and he thought the oath pact was a permanent solution. And being a Shard does warp their minds, as Odium indicated

This has two possible meanings. It is possible that Honor thought that the cycle of desolations would be eternal.

It is not possible that he thought that they would stay on Braize forever. He took too many preparations for combat on Roshar for that. The Heralds have a set program to teach the people, they have their Honorblades. New bodies are arranged for as soon as they go to Roshar. Is is possible that the Stormfather was too alien to understand, but not Tanavast.

[Karger]

57 minutes ago, Oltux72 said:

It is not possible that he thought that they would stay on Braize forever. He took too many preparations for combat on Roshar for that. The Heralds have a set program to teach the people, they have their Honorblades. New bodies are arranged for as soon as they go to Roshar. Is is possible that the Stormfather was too alien to understand, but not Tanavast.

The stormfather claimed otherwise and given the number of desolations they probably came up with a system.  We don't know the real purpose of honorblades or when exactly they were made, the set program seems like something a group of smart people could come up with easily enough, and the new bodies could just be a form of healing.  We don't really know the full mechanics of how that works.

[first void]

Need to remember one thing. This time is different. We have Hoid snooping, hoppers interfering, heralds dying for reals, and Cultivation giving out therapy. Further more, I am pretty sure the fused eventually devolve into whatever holds the thunderclasts together, and from there can be killed for reals. The heralds are also broken beyond helping, Odium is also seeming to lose the support of some of the non-fused parshmen. Even to the point of two becoming bonded to radiant spren. This is the endgame. I see a big investment in this one from Odium. It is not a normal desolation.