Theoryland of the Wheel of Time

Elantrians are not slivers. Mistborn trilogy spoiler warnings follow! The Lord Ruler was indeed a Sliver. So was Vin. For the rest, I would say probably not.

What defines an actual Sliver of Adonalsium is not as clear-cut as you might think. It's a term that in-universe people who study this have applied to various existences and states. Every single person on the world of Scadrial has a bit of Leras in them—a bit of the power of Preservation. Every single person has a bit of Ati in them. There's a certain threshold where these scholars would call you a Sliver of Adonalsium. But I would say that any regular Misting is probably not a Sliver. A full Lerasium Mistborn is getting closer, but people who have held one of the powers are what would probably be termed a Sliver by the definitions. If you hold all the power that makes you a Shard, but the Lord Ruler held a little bit of it and then let it go. From then on they referred to that change in him—the residue, what was left—as a Sliver. When he held it he became the Shard for a short time, and Vin was a Shard for a short time. After Vin gave up the power, what Kelsier is at the end of the trilogy—that's a Sliver of Adonalsium.

"Is the definition of Sliver: Someone who has held a large part of the raw form of a Shard temporarily?"

"That is it"

"How is a Splinter different from a Sliver?

"Let me see... You have met splinters in Elantris, Warbreaker, and in Way of Kings. You have not met them in Mistborn."

PUCK

"I feel like we know that. So, qualitatively, what's the difference?"

BRANDON SANDERSON

"Qualitatively, they're reverses of one another. A Sliver is a human intelligence who has held the power and released it. A Splinter has never been human."

PUCK

"But it derives from a Shard's power."

BRANDON SANDERSON

"Yes. That's not it completely, but there's at least something to think about."

At the end of Alloy of Law, Marsh tells Marasi, that Wax is doing "his brothers work". Does this mean Kelsier is still meddling, or is this a continuation of his initial legacy?

Kelsier has never been good at doing what he's told. He's still interfering.

An event happened long ago which destroyed something called Adonalsium into 16 pieces. And 16 people took up that power.

Question

People?

Brandon Sanderson

I call all intelligent species people. If someone takes up the power and lets go of it, it has the effect much like a balloon that's been stretched and then the air is let out. I call that a Sliver; based off of the Lord Ruler calling himself the "Sliver of Infinity". The Lord Ruler is someone who held the power and then released it. And so, current Slivers are the Lord Ruler, Kelsier, and there may be others around who at one point held the power and let go of it. A Splinter is a term used by certain people in the cosmere for power of Adonalsium which has no person caring for it, no... no person holding it, which has attained self-awareness.

Wetlander

So is that like the mists and the Well? Are they...

Brandon Sanderson

They are not, because they have not attained self-awareness. But, the Seons are self-aware. So, any piece, for instance there were some spren on Roshar before Honor and Cultivation got there. Those were already Splinters of Adonalsium where he had left power which attained sentience on its own. So, it can be intentional is what I am saying, does that make sense? You have seen other splinters.

Wetlander

Are the highstorms related to the splintering of Honor?

Brandon Sanderson

The highstorms are more related to the mist from Mistborn which terminology we have not discussed yet. You have seen splinters quite a bit on various planets.

What kind of changes do Slivers go through after letting go of a Shard's power?

It leaves them, imagine it like a balloon that has been deflated.

Ok so would Rashek still have had powers [because he was a Sliver]?

He would have had some residual effects. But it also works the soul in weird ways, like a balloon that has been deflated.