Telepathy, definitely. And Gideon should have necromancy, and they should be able to use necromancy around each other. 

...But, more seriously... Some way for Gideon to control her end -  she wants the balance of power to be equal, pretty much? And then submitting her power to Ellyn is an ongoing choice, not something her prior choices are trapping her into? 

Reasonable, yes.

So the difficulty is that all examples of Lyctorhood they have involve moving souls around, whether in whole or in part, all irreversible, and all located within one or both bodies. She's not sure how reversible soul-stuff can be, really, they don't tend to do well without bodies for preference or at least some sort of physical anchor.

At least in the physical world. The River works differently. Souls behave differently there. Lab Five demonstrated that it is possible to carve out some kind of constant space in its ever-moving flux, at least at the shores. So. What if. What if they hid their Lyctorhood in a bubble in the River somehow. Where it would be theoretically easier? possible? to pick it apart at a later time.

The whole line of thinking goes beyond theory, really, into almost entirely uncharted water but- It should leave Gideon able to end it on her own if she wanted, since she'd have the necromancy to get there. Getting back without- different proposition, so that's not... great. Depends on the mechanism, could Ellyn get her necromancy without the rest of the package, actually could Ellyn do that in advance and then she and Gideon would be approaching the merge from a whole other angle- Tangent. Might not even be possible for anyone who's not Tamerlane.

...One major advantage to a reversible process is that, if they figure out a better way later, they can unravel what they did and then change - and in that case, Ellyn could help Gideon get back. 

...Also Gideon specifically might survive getting dumped in the River without necromancy, especially if her body is still outside.

Mm. There's that.

But, hmmm, with the calculations she's been doing - she thinks the Lyctorhood they could achieve with a mutual approach would be superior, more stable, but the problem is that giving Gideon necromancy really isn't mathing... This could take - years, maybe. 

...She's inclined to say go for a prototype, reversible process now. 

They'll have forever to work out the rest of it. And maybe Tamerlane can help.

Part of why it's better to front load efforts to help Tamerlane.

Yeah.

Kiss!

She feels ready, just about - a few adjustments and calculations still need to be made, but... They're so close. 

They are. She wants to talk to the Fifth about the River some, to make sure she gets the bubble part right, and that work will need to be checked. Don't want it eroding away. And then they'll need to find a way to almost die at the same time, or close to it. Might be a good idea to enlist some help watching over them so they don't actually die, as well.

They've got an entire team. 

Best to put them to use.

Might have been the prior Lyctors' issue, really - they didn't work together, and they didn't acknowledge that Ninth House Best House. 

Sad. But now they're all wiser with the weight of experience.

Learn from others' mistakes and all that. 

Exactly.

Then, once Ellyn has the bubble ready, it's time to get the Sixth and the Third to guard them while they almost kill themselves.

Phaedelia is, at least, taking this responsibility very seriously. 

It will be walking a bit of a knife's edge, if one will excuse the pun. But they won't let the Ninth fall.