I know I submitted some work with ideas about a servitor race for TNK and perhaps corrupt merfolk-but looking at these octopus, this is kind of unique and its one the various creatures known to live in The Styx. They're octopus like which is cool and they inspire obyrithian madness which fits with TNK. I think these or something statted just the same way would be a good servitor race.
http://www.wizards.com/default.asp?x=dnd/we/20060620a&page=1
These eat memories (I like how they represent that) through simulated negative lvls (which makes you "forget" how to fight as well or skillfully as normally). They arent caused by negative energy so D-Ward doesnt prevent them, nor do they actually result in actualy negative lvls so some feats that let you ignore X negative lvls dont work, nor would you die by having too many of them. Still, like neg lvls you would take penalties to skills and other roles and lose abilities that you wouldnt have at your Effective Level. They persist until you remove them. They also have modify memory as a spell like ability.
(No art provided of the creature. {notice the lil lady} Now, they dont START this large, but HD scales up to Gargantuan. I like either this:)
(or this:)

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