This is my first attempt at deckbuilding, so be kind and cut me some slack for any glaring mistakes. Obviously, I welcome any tips and tweaks, I have no idea if this would actually work.

It's pretty self-explanatory; terror, terror and more terror, use Broken Time to get Hastur in asap. The single Tulzscha in there was pretty much an afterthought after I realized most of my characters were Cultists. It's a way to use a second Broken Time - assuming I don't draw Tulzscha myself.

My card pool is fairly limited - hell, I don't even have all of these cards yet - but I've tried to make do. Feel free to add stuff from whichever pack, though - in fact, I encourage it - it would be nice to know where to go next when purchasing.

Character
Bearer of the Yellow Sign (Core) x3
Bringer of Fire (AH) x3
Byakhee Servant (Core) x3
Hastur (TSC) x3
Mad Artist (Core) x3
Messenger from Beyond (Core) x3
Moonbound Byakhee (TGS) x3
Tulzscha (KD) x1
Victoria Glasser (Core) x3
Victoria's Protege (SftSK) x3

Support
Scalpel (TGS) x3
Stygian Eye (IT) x2
Victoria's Loft (Core) x3
The King In Yellow Folio (LR) x2

Event
Broken Space, Broken Time (CoC) x3
Lost to the Madness (TC) x3
Power Drain (Core) x3
Scotophobia (Core) x3

 Broken Space, Broken Time is tricky of course, as your opponent might get that free Ancient One as well.  But it is fun to play!

I think you might not have enough 1 and 2 cost characters in there.  I like the Dangerous Inmate in this role.  Sometimes the Giant Albino Penguin as well.

I originally planned on making a similar deck, but I ended up combining it with Cthulhu because it gives you a lot more options insanity wise, and serpents are great characters in terms of terror icons.

Cards like Sleep of Reason let you monopolize a story while the attachment is present (since you now have 4 terror struggles). Additionally I highly, highly recommend Seeker of Mysteries (neutral) as she helps you get Hastur, Lord of Carcosa into play quicker and he is the absolute key to an insanity deck working.

 You might want to consider The Enchanted Woods - it lets character with terrify go insane.  It's an interesting card in the right situation, but probably not competitive.

I also recently put together a mono-Hastur insanity-themed deck, I will post it when I get a chance, but I do have a few quick thoughts.

Dangerous Inmate would be a good addition, but I prefer Deranged Diva.  Either way, you get one "free" insanity a turn once they're out, which is really useful.  Also, I would seriously consider adding Horrifying Daydreams; I think you need an event-based insanity in addition to your character-based insanity effects, as otherwise you could face serious trouble if your opponent has a way of keeping your characters out of play (e.g., getting repeatedly hit with the Initiate of Huang Hun).  Also, Apeirophobia - just an amazing card all around, it honestly belongs in nearly every Hastur deck.

I might also recommend Julia Brown (the neutral one). She combos well with tons of insane characters…

Runix said:

I still prefer Dangerous Inmate between the two.  Diva works on a wider range of characters, but Inmate lets you pick your target and overall I think I like that better.  Too often Diva just drives some useless 1-cost weenie insane where Inmate can take out a specific problem character or make someone drop an Attachment you'd like to get rid of.

Thanks for all the feedback, and also to Hellfury for the reply on CGDB.

I noticed that Hastur characters are fairly… well, ass; but I had hoped that with almost 7 cycles printed, some decent characters would accidentally have found their way into the game.

All the characters recommended so far cost 2. Are there any 1 cost chars in Neutral/Hastur worth getting? Or do you think the deck could work with 2+ only? I was actually thinking of adding Granny Orne, but she's more of an event than a character.

Also, any ideas on what I should remove? Moonbound Byakhee, I guess?

I like Long Dead Prince as a cost 1, he works very well as an early blocker and having Combat can keep some enemies away from stories.

I also like Obsessive Sycophant, at least in some decks (those with low Arcane).  If you get a chance to send him to a story unopposed he can reready with Arcane, but more commonly he can wait and see your opponent's story commits and then provide AA where it is needed to keep your top characters readied for defense.

Ghost is not a bad blocker either, although he lacks any icons so I tend to prefer Long Dead Prince.

Among the higher cost characters, some of the Byakhee are handy for providing decent icons and Fast, it all depends what you want to do.

Personally I've had better results from including more take control effects and not relying as heavily on Insanity which I feel is a bit unreliable.  Too many characters have (or can get) Willpower or Terror.  There are events and abilities that can strip it off, but to really make the deck hum you may need to apply these nearly every turn which is going to sap some of your card draw and/or domains.  By having multiple tools, you have better odds of having something that can *efficiently* deal with an enemy character rather than needing extra steps.  In particular, cards like Stygian Eye work extra-well on characters that can't go insane because you can keep them permanently (or at least until you send them to their deaths).