Wyan of Bodach info

[(Psi)SeveredHead]

Correct. Rajaat was actually a pyreen (note there was no champion dedicated to wiping them out).

He wanted to reverse the tide of history, putting the progenitor race, the halflings, back on top. His favored servants are essentially mutant halflings. They're called Shadow Giants. (Since 4e has erased Rajaat, the Shadow Giants have no halfling traits anymore. Lame.)

4e also changed the concept of pyreen to an epic destiny

 

[bganon]

4e doesn't have much to say about Rajaat and the early history of all the champions, so it can be up to the DM. I personally didn't care much for all the detailed Rajaat/pyreen/halfling shenanigans, but YMMV.

But in the novels, Sacha and Wyan were beheaded by Borys (now the Dragon) for remaining loyal to Rajaat when all the other champions turned against Rajaat. Also, I don't quite remember but my impression was that Sacha and Wyan weren't exactly "undead", at least not much more so than some of the sorcerer-kings (who also manipulate and feed on life force), it's just that they were powerful enough that simple beheading wasn't enough to completely kill them. Kalak later used them as advisors to gain power, but even as shriveled heads they retained some of their power and were rather dangerous (and never to be trusted).

Sometimes people find it hard to take a dude named "Pixie Blight" seriously, but think about it: can you imagine how difficult it must be to hunt down and destroy every last pixie? 2e pixies in particular were typically constantly invisible, carried arrows that rendered targets comatose or erased their memories, and could cause permanent confusion just by touching you. Wyan was hardcore.

 

[Alzrius]

Also, I don't quite remember but my impression was that Sacha and Wyan weren't exactly "undead", at least not much more so than some of the sorcerer-kings (who also manipulate and feed on life force), it's just that they were powerful enough that simple beheading wasn't enough to completely kill them.

The novels never said, either way.

Sacha and Wyan were disembodied heads that were still active, and they both enjoyed drinking blood, but that's about all the evidence that we have either way.

Both were still psionic, and the one time Agis (in The Obsidian Oracle) attempted to attack Wyan's mind, he began destroying parts of it...to absolutely no effect. Wyan simply smirked that his "mind was at rest" and had been ever since he killed the last pixie on Athas.

This could be taken as evidence that undead are immune to mind-affecting effects (in 3.X), but the books were written during 2E, which was inconsistent on this particular point (and Dark Sun specifically seemed to allow for mental attacks against sentient undead).

So Sacha and Wyan's status post-beheading is likely to remain unresolved.

 

[(Psi)SeveredHead]

Sacha and Wyan were epic-level psions (you would need to be a 20th-level wizard/psionicist to have been a champion). It's entirely possible Agis just couldn't tag 'em mentally.

Mind you, that didn't work in the rules. Either Agis (a 16th-level character) was using the power score system, in which case any of his powers would have a greater than 50% chance of "tagging" (the system didn't normally allow saving throws, or indeed allow higher level characters to do anything about telepathy) or he could use MTHAC0 (raising MAC was nearly impossible, so Agis should have hit).