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Telepathy out to 10' per HD is kind of crippling. That means not being able to talk to other people in the same room as you.
Well, that's how the original class communicated. She was capable of telepathy but incapable of speech.

All skills should not be class skills. That gives you access to iajitsu focus, hypnotism, craft dreamweave item, and so on... skills with concrete in-game benefits that can really power you up. Also, it's the factotum's schtick that you're messing with.
That was a suggestion by Gorgon. I personally agree with you there.

Needs more flavor text in ability descriptions, so we've got a better idea of what's going on and why. You mention a tempest lash, but I frankly don't have a clue what that is, especially because there's no source.
Okay.

Home Plane:
I don't like that you named it for the player. Let the players name their own dark library.
WOTC named it actually. Otherwise, yeah, I'd have left the name blank. I'll probably do that anyway since the first name is impossible to spell, and the second seems about as subtle as a brick to the face.
Being able to transport to the library is fine. Not having a way to transport back is... inconvenient.
good point.
This strikes me as an ability fitting for a much higher level than 4th.
It was originally, but I think somebody suggested that it made more sense as a lower level ability. Not sure what my reasons were for putting it at 4th.

Infinite Knowledge:
Seems like a kind of overpowered version of Knowledge Devotion. The problem with skill-based abilities is that they either don't work at all (truenaming) or they're too easy to pump, granting ridiculous bonuses.
The 13th level bonus sucks. A bonus to AC granted around the time that AC really has started to decline in usefulness. I can't see smart players using it.
The 16th level bonus is weird and ill-fitting. I can't think of a better way to say it. "DCS" is confusing (Save DCs would be better, but still awkward), and there's really no precedent for an ability like it. Replace it?[/]
I think this was a suggestion by Gorgon based off of the Marrutact.

Combat Expertise:
[The thing about combat expertise is that, as a feat that's a prerequisite for so many other feats, it's one you take early or you just don't take it at all. As such, it is out of place at 5th level.
Okay. I just thought the first couple of levels were kind of front loaded already.

Damage Reduction:
"The miss chance increases by 10% every time she takes another 2 levels in the class for a total of 40% at 14th level. " - wording is awkward in the underlined part there.
So... I have 40% chance to dodge any attack at 14th level. I've also got the dodge bonus from combat expertise, so that's... 5%? 45% chance to avoid any attack. I'm also getting +5 to AC in addition to my existing bonus, so my AC is maybe going to prevent what? One in five attacks on its own? Seems a little much, numberwise. It strikes me that with some other abilities and/or concealment benefits, you're nigh untouchable (Say, warlock's entropic shield, as a start).[/]
originally it was just a flat twenty percent. Should I just go back to that?

[quote]Knowledge Devotion:
What would happen if I, as an Illurien with skills stacked to maximize knowledge, huge int, int bonuses from levels in the class, item familiars granting +20 or more to the knowledge skill of my choice, picked up the Knowledge Devotion feat in addition to the bonuses granted here? Stacking! Too easy/intuitive to abuse.[/] Thanks for pointing that out.

Rejuvenation:
Kind of crippling if you don't necessarily get a choice in the matter. If I'm the BBEG trying to defeat the party, I'm going to kill the Illurien over and over, and run away after each time.
Have any suggestion for how to implement it then? Somebody suggested the level drawback to balance out the unlimited amount of raise dead/resurrect or whatever it is.

I complained about the number of rolls with storm of knowledge, and I complained about the number of things that tempest lash got, goodie wise. I fear the experience tracking makes a full attack routine by the Illurien into a bit of a headache (You're rolling vs. ac, doing damage, recording damage to the monster on the sheet, rolling int damage, recording changes to the monster on the sheet, adjusting stats where needed, calculating hp gain, adding to your temporary hp pool, calculating XP damage, adding to your special XP pool... and you're doing all this potentially twice a round, several rounds in a row.
The XP thing was a suggestion by Magicypop. After pointing a bunch of stuff out, I agree there's too much rolling. Any ideas on what to do to reduce the amount?

Improved SLAs:
]Too vague, a little rushed.
I can add, what? Two spells, period? Or two spells for each level?
The number of times it's usable per day is awkwardly worded.
supposed to be per level to kind of represent the endless pursuit of knowledge. It was just an idea and I expect it's more powerful than I intended.



Okay, I'm addressing your various points here Hyudra. I've edited a few things out because I've already addressed them.