Here's another rundown for the Spider Blood Assassin.
You have "blade" instead of "weapon".
Aranea Shell - This ability needs to be tagged.
Drain the Fluids - Do you intend this ability to work on Elementals? Otherwise you need to specify it doesn't since Elemental became a subtype of Outsider in Pathfinder.
Tarantula's Tool - Now, do they gain the same chompers of a Tarantula or just sharp teeth or what? Something I like to do when I make base classes that grant natural attacks is that they can grow and dismiss them (usually standard to grow, free to dismiss for me) so that they don't impede them socially. Otherwise, this ability is fine.
Unrelenting Grip - This ability needs to be tagged.
Weapon Training - While both are still subpar feats, this is definitely better.
Advanced Assassin Techniques
Mark of Kaine - *chuckles*
Anyways, the end of the last sentence looks like a copy/paste error.
Whispers of the Web
I would just word this as something like, "A Spider Blood Assassin of twelfth level or higher can converse with Arachnids as if they shared a language." and make it a Supernatural ability. Sp abilities generally require a direct activation, not a passive benefit.
Also, I would change this to only allow conversing with spiders and spider-like creatures, not arachnids. The issue arises where you'd require the players and DMs to know what is an arachnid and what isn't and that this ability would allow conversing with scorpions, ticks, mites, harvestmen and solifugae (though if you meant that, it's fine).
Nest of Fangs
You forgot "can" after "Assassin".
A permanent duration is a little much, even if you can only have one swarm at a time. This means the swarm will always be following you once summoned and you'll need to keep up with its day to day needs. I'd suggest changing the duration to a set amount of time (like an hour or two) and giving the option for dismissing the swarm prematurely.
And this is more just something I like to do while formatting abilities, but can I suggest making a [list][/list] of what the changes are?
A Thousand Eyes
As what spell?
I'm a little confused with this one. If the spider already has to be willing, what is the exact purpose of this ability? What do you and the thrall get out of it?
I really like how you've updated the class.
Alright, time for a rundown on the Theg.
I must admit that my knowledge of the Realms is honestly very threadbare. I've read a few of the Drizzt novels and I have the campaign setting sitting around here somewhere, but that's about it.
Plowing on though, I really like how they've domesticated Ankhegs. For some reason those monsters have always been a favorite of me and mine and it's a nice touch.
I'm guessing ceratinous/keratinous is a regional dialect thing?
Do they look like any beetle in particular or are they just generically beetle-like?
I think you meant "subduing".
It looks like you haven't finished writing this part. But I am curious on something; you make mention how a Theg separated from the collective withers and dies. Why is this different than an adventuring Theg?
You have "o" instead of "to".
You have "ar" instead of "at".
I think you meant "deeply" instead of "deep".
Ability scores - Sturdiness and Memory would entail a Constitution and Wisdom bonus, not Strength and Intelligence.
Movement speed - There is none listed.
Visions - There is none listed.
Hivemind - I'd clear up how this is worded to make it more in line with other racial abilities. Also, I'd reword the positive so that as long as any Theg are within range of each other, they all have to be caught flat-footed/flanked for any one member to be caught flat-footed/flanked.
Ancient Netherese Patronage - You can make Knowledge checks untrained as long as the DC is 10 or lower, so you may want to clarify what this ability does exactly.
Well, they're certainly long lived for insects.
The Weight Modifier is a static number in Pathfinder, it's not rolled.
Now let's do a rundown for the Worm-Eaten Collective.
The second paragraph confuses me a little bit. Is the goal of this class to gather drones under their control or are they trying to destroy the Collective as a whole or what? And why is Rival capitalized?
Alignment - I don't know about Chaotic, but this class definitely should require an Evil alignment. You're transforming creatures against their will into meat puppets for your own use and power and the spell required to enter the class has the "evil" tag.
Spells - I'd reword this to say something like, "Must be able to cast arcane spells (one of which is Fleshworm Infestation)."
There's only 1 f in Profession.
You forgot to add in the class' name.
Spells Per Day
So if a Wizard 7/Cleric 1 took all 10 levels in this class then they could choose to progress their Cleric casting and cast as a Wizard 7/Cleric 9?
What is the significance of 5 hp or less? Generally abilities like these require the target to be helpless, unconscious or asleep.
Three different will saves feels a little superfluous honestly. If there were varying results for failing or saving against different amounts of the saves I could see justification for 3 saves, but not as it is now.
You do realize that the scale of resisting Horde starts at 2 HD or more (with the first level of this class taken) and ends at 5 HD or more (at 20th level). Did you intend for the horde the character controls being mostly weak NPCs?
Is there a cap on the insight bonuses?
Hoo-boy. That there is a massive drawback to the class, especially with how weak your individual horde members are.
I think this ability needs a tag of some sort or a break down of what parts of Ex, Su, etc.
Natural Armor Increase
The fluff for this matches more with Damage Reduction than Natural Armor. And I'd personally rename it to be less literal and clunky, but that's just me.
This ability needs a tag. And you're really starting to get into some serious bookwork with this class now and I wonder if you may be breaking the action economy here with your high grade minionmancy.
Pain of the Horde
You should give a range for this ability.
I think this needs an (Ex) tag since you didn't use the feat's name as the feature.
This ability needs a tag and a range.
And..um...wow. This ability is really, really powerful. Game breakingly so. You drop the HP on a maximized size horde by just 10 and you're getting +20 Con, +20 Charisma, and +20 Caster level.
This really needs to be toned down.
That is a 3.5 stat block. Could you please reformat it to the Pathfinder one I provided? Also, you may want to check it against the Monster Creation Guidelines that Paizo put out.
Again, this is a 3.5 set up. I didn't remember to provide an example one when setting up the contest, but I'll add one in when I get the chance. In the mean time, please use the Lich as an example.