Observations of the Secrets of the Reshi Isles

[Frustration]

WaT showed us that Chasmfiends went to the shattered plains to use the power of Odium's perpendicularity to undergo their metamorphosis. Dawnshard showed us that the Lanceryn went to Aimia to use the power of the Dawnshard for the same reason.

 

So that leaves us with a pattern, where two of the largest greatshells on Roshar go to various fonts of external power to reach their large sizes. One however stands as an interesting exception: The Tai-na, the Reshi isle greatshells.

 

Despite being much larger than the other greatshells, we have no particular source of power for their transformation.

Some possibilities for this power source include:

• Honor's perpendicularity: it moves around like the Tai-na do, and it rejects the touch of humans, but not necessarily of the Tai-na.
• Another Dawnshard: we know that there were multiple on Roshar at one point.
• Wind/Stone/Night: Possible, but I think highly unlikely.

As for my thoughts: I'm honestly not sure. I am convinced however that there is some source of enormous power within the Reshi sea. 

[Trusk'our he/him]

1 hour ago, Frustration said:

WaT showed us that Chasmfiends went to the shattered plains to use the power of Odium's perpendicularity to undergo their metamorphosis. Dawnshard showed us that the Lanceryn went to Aimia to use the power of the Dawnshard for the same reason.

 

So that leaves us with a pattern, where two of the largest greatshells on Roshar go to various fonts of external power to reach their large sizes. One however stands as an interesting exception: The Tai-na, the Reshi isle greatshells.

 

Despite being much larger than the other greatshells, we have no particular source of power for their transformation.

Some possibilities for this power source include:

• Honor's perpendicularity: it moves around like the Tai-na do, and it rejects the touch of humans, but not necessarily of the Tai-na.
• Another Dawnshard: we know that there were multiple on Roshar at one point.
• Wind/Stone/Night: Possible, but I think highly unlikely.

As for my thoughts: I'm honestly not sure. I am convinced however that there is some source of enormous power within the Reshi sea. 

An interesting idea. I hadn't considered it before.

It seems likely, given all we know. Plus, having a big conduit for power there would be a cool plot point for the Voidlight Archive, one that Tetribution overlooked initially. Maybe there are more moon pieces there to block such senses?

I also don't recall it being explicitly stated that the Lanceryn needed the Dawnshard's presence to grow, just that they needed the bigger Mandras that lived there, but it's been a while since I read Dawnshard and it would track pretty well.

Edited January 16 by Trusk'our

[Nitpicking]

Lanceryn are not greatshells, are they?

[Frustration]

5 minutes ago, Nitpicking said:

Lanceryn are not greatshells, are they?

They are/were.

[Elite01]

Just stab in the dark

could a god metal give off some kind of radiation? Could there be a chunk of honor or odiums metal in that location that helps them grow larger? 
I think it’s unlikely but all I can think of when there probably isnt a perpendicularity out there (unless honors is moving around there) 

[NovaRay He/him]

I don’t think godmetal gives off radiation since atium, lerasium, and trillium didn’t. I don’t know about raysium, tanavastium, or cultivation’s godmetal.

[JustQuestin2004 he/him]

Axie's seems to believe that the cause must be from whatever Spren that they Bond with. And that these Spren must be 'spectacular' compared to the other kinds of Spren that bond with other Greatshells.

So, they need to be quite powerful, likely much more so than even the Mandras from Aimia. And they aren't a Unique Spren since an entire species bonds with them.

Maybe it could be the Stormstriders? The very large Spren that walk in the Highstorm that have been seen intermittently throughout the books? With how large they are and the fact that they existed entirely within what was once the main source of Investiture on Roshar, they must have plenty of Investiture in them. Possibly enough to allow for the existence of ridiculously large Greatshells like the Tai-Na?

[Myst He/Him]

So, I found these

Spoiler

AhoyMatey (paraphrased)

Do all greatshells have spren?

Brandon Sanderson (paraphrased)

In order to survive with the science that I built, the greatshells almost all require some sort of spren to keep them from collapsing. (I suspect greatshells in the water may not require them.)

Words of Radiance Seattle signing (March 8, 2014)

Spoiler

Questioner

Are there any greatshells in Roshar's oceans larger than the ones we've seen?

Brandon Sanderson

No.

Questioner

So the Reshi Isles--

Brandon Sanderson

The Reshi Isles, that's the biggest, and even with that I'm doing major fudging on the square-cube law. They've just spren-bonded, we'll talk about this. But even with the spren, those are a stretch. That's as big as it gets. They could exist in the oceans because the square-cube law doesn't apply the in same way, with buoyancy and things. But I think we don't need anything larger than islands.

Questioner

No Godzilla?

Brandon Sanderson

They're bigger than some version of Godzilla.

Arcanum Unbounded Chicago signing (Dec. 6, 2016)

So, I found these, which suggests that the Tai-na might not actually be bonded to Spren. In both of these, Brandon doesn’t confirm it, however. I think this suggests that they don’t, but for consistency, I can see why he’d make them bond Spren, even if they don’t need to.

In the case of needing Spren and such. I’m leaning towards Honor’s perpendicularity. We’ve been told that Honor’s perpendicularity was random, which doesn’t make sense

Mistborn spoilers, I’m not sure which book exactly though.

Spoiler

Basically, Preservation died, yet his perpendicularity didn’t move around until Rashek and later Sazed, moved it intentionally. Honor’s perpendicularity should behave in a similar way.

Plus, we have examples of people being wrong about this. We were told that Odiums perpendicularity was lost, yet several people knew where it was, and it was responsible for the Chasmfiends source.

I find it likely that Honors perpendicularity does one of two things:

A. It moves, that’s consistent with some stuff in the book, and makes sense with what we know. And the Tai-na can sense where it is, and travel to it much like the chasmfiends do.

There’s another WoB that states that they can go on land

Spoiler

Blightsong

Have larger landgoing greatshells existed above a chasmfiend?

Brandon Sanderson

Larger than a chasmfiend... the ones that wander around out in the islands of Reshi could go on land. So yea, it is possible that there are larger ones. They do better in the water, because of how big they are, but the high oxygen, low gravity, and symbiotic bonds with the spren allow some mega fauna that is just really large and just could exist on earth, so yea.

OdysseyCon 2016 (April 8, 2016)

And so I thinks it’s possible that they could do this, and this fits. My only concern is that people would probably see the Tai-na traveling for this.

B. This is what I think is likely, but has a few complications. So, basically, Honor’s perpendicularity doesn’t move, it’s somewhere remote like Odiums perpendicularity. I think this because perpendicularities don’t behave like this, and this is the only time this has happened. At least to a shard powered perpendicularity. Which leads to my second thing. Just like we have perpendicularities on Threnody acting weirdly, something similar happening on Roshar could potentially be happening, which people confuse with honors. And then the Tai-na just go to Honors actually one. 

So, both of these have problems. The first with that people would probably notice greatshells wandering on land to perpendicularities, it’s not really something you can miss. The second theory has problems with the book slightly lying to us, and the unexplained part of where the random perpendicularities are coming from.

I personally think that the Tai-na dont have Spren bonds, but if they do, Honors perpendicularity seems likely to me

[JustQuestin2004 he/him]

20 minutes ago, Mistfallen Soldier said:

I personally think that the Tai-na dont have Spren bonds, but if they do, Honors perpendicularity seems likely to me

But if that's the case, then why does Axies, the guy who has spent literal millennia studying Spren, think that they have a Spren in their massive Gemhearts? The, in his own words 'Soul of their god'. Asking about it got Axies strung up, though that's probably more because he's an Aimian.

[Myst He/Him]

16 minutes ago, JustQuestin2004 said:

But if that's the case, then why does Axies, the guy who has spent literal millennia studying Spren, think that they have a Spren in their massive Gemhearts? The, in his own words 'Soul of their god'. Asking about it got Axies strung up, though that's probably more because he's an Aimian.

Well, I don’t think they do based on the WoB, but I can see why they would. Also, Axies doesn’t know everything, he can be wrong, just because he thinks there are, doesn’t mean they exist. As for the Soul of the Gods, it is likely that it is a Spren, but people see luckspren(mandra) occasionally, and I feel like they would comment on it.

I may be wrong, I mentioned how he might keep it consistent, and that would explain things, but at the end of the day, until we get a confirmation, everything kinda is just as likely as everything else(I know that’s not how probability works)

[JustQuestin2004 he/him]

49 minutes ago, Mistfallen Soldier said:

Well, I don’t think they do based on the WoB, but I can see why they would. Also, Axies doesn’t know everything, he can be wrong, just because he thinks there are, doesn’t mean they exist. As for the Soul of the Gods, it is likely that it is a Spren, but people see luckspren(mandra) occasionally, and I feel like they would comment on it.

I may be wrong, I mentioned how he might keep it consistent, and that would explain things, but at the end of the day, until we get a confirmation, everything kinda is just as likely as everything else(I know that’s not how probability works)

Fair enough, I just prefer for what's in the books to take precedence over WOB's, they're only semi-canon until fully confirmed in the books in my eyes.

[Myst He/Him]

11 minutes ago, JustQuestin2004 said:

Fair enough, I just prefer for what's in the books to take precedence over WOB's, they're only semi-canon until fully confirmed in the books in my eyes.

That’s fair, but since both my theories for where they’d get their Mandra’s have problems. I think it’s the best option for now 

[Nitpicking]

On 1/19/2026 at 1:22 AM, Mistfallen Soldier said:

I find it likely that Honors perpendicularity does one of two things:

A. It moves, that’s consistent with some stuff in the book, and makes sense with what we know. And the Tai-na can sense where it is, and travel to it much like the chasmfiends do.

We know Honor's perpendicularity moved (back when it existed). Dalinar was opening Honor's perpendicularity. It never had a single location, normally it traveled with the Stormfather.

[Frustration]

2 hours ago, Nitpicking said:

It never had a single location, normally it traveled with the Stormfather.

We don't know it traveled with the Stormfather, and indeed I would find it very dubious that he couldn't sense Ishar summoning it if that were the case.

[Nitpicking]

On 1/21/2026 at 9:02 AM, Frustration said:

We don't know it traveled with the Stormfather, and indeed I would find it very dubious that he couldn't sense Ishar summoning it if that were the case.

When did Ishar summon Honor's Perpendicularity?

It moved with the Stormfather. How do you think the Highstorm charged gemstones? You need a Connection to the Spiritual Realm to do that. 

[Frustration]

32 minutes ago, Nitpicking said:

When did Ishar summon Honor's Perpendicularity?

On scene in RoW, where the Stormfather himself said that he couldn't even feel the Perpendicularity move.

Additionally he had to have been doing it multiple time as that's how he got the Tukkari into the CR that Adoilin fought.

35 minutes ago, Nitpicking said:

It moved with the Stormfather. How do you think the Highstorm charged gemstones? You need a Connection to the Spiritual Realm to do that. 

It clearly did not as the Highstorm does not appear when Dalinar summons the Perpendicularity. Additionally Dalinar can recharge gemstones and Radiants by touch without the perpendicularity.

A Connection to the SR yes. Honor's perpendicularity no.