NOTE: I have never played this deck, I'm missing 9 cards from it (1 that hasn't even released yet). So I have no clue how this plays. This is pure theorycraft. I am saving dust to get this deck tested out myself, I'll write a better guide when I know how to pilot my own deck.  :P

This is my second C'thun deck in my quest to homebrew a C'thun deck for every class.  However, this time C'Thun has to share the spotlight with another old god, Yogg-Saron, Hope's End. My reasoning for combining the two is Cult Sorcerer, because with this card out, whenever you play a spell you're buffing both old gods. When playing this deck, remember C'Thun is your primary win condition, Yogg-Saron, Hope's End is a potentially swingy support card but can kill itself so...

Card Choices:

-Raid the Sky Temple: This is here for supporting Yogg-Saron, Hope's End and to a lesser extent Cult Sorcerer. If your playing this before SoU, you could use Open the Waygate

-Archmage Arugal: Our friend Archmage Arugula is here to support C'Thun by adding more copies of his support cards or if you are lucky two copies of C'Thun himself (or Yogg-Saron, Hope's End)

-Luna's Pocket Galaxy: After the buff, I could see this card is being used. The dream is to hit one of your old gods to only cost one, but it's also nice to make your other C'Thun support cards cost 1.

-Stargazer Luna: I was considering this or Aluneth, and I picked this. Good card draw, especially after you play Luna's Pocket Galaxy

Other Cards to Try:

-Frost Lich Jaina: The reason I didn't include this card is it would interfere with your quest hero power, Ascendant Scroll. However, it's always a nice card for late-game matchup's

-Zilliax: Fits in every deck, could probably provide support to this deck too.