So just bought the game today and my son and I enjoyed our first session.

Question, becuase it's not clear...

The actual card for Cthulu says that when a player draws two cards, he must sacrfice a creature if able. Does this mean BOTH players or just the player that control Cthulu?

Silly, I know. But I've played a fair number of games where actions like that hit everyone.

The specific language is " After a player draws cards during his draw phase, he must sacrifice a character, if able." From this language we can see that the effect is targeting a player who is drawing cards. So, the sacrifice applies to that same player.

In other words, for this card, only the player who drew cards during the draw phase must sacrifice a card.

As a general note, if you control Cthulhu, and have no other characters in play, you will have to sacrifice Cthulhu to meet the requirement. This is something that new players occasionally don't recognize.

Right...but my question revolves around do ALL players need to sacrifice when they draw?

So if my son plays Cthulu, do I need to sacrifice on my turn when I draw?

Yes. Once the card is in play, the text is ongoing and applies to everyone. If it was meant to be specific to a single player, it might say something like "you" or "your opponent(s)". But the use of "a player" means that it applies to everyone.

Is it possible to sacrifice Deep One Rising for Cthulhu and then bring it back into play with Hydra to destroy an opponent's character every turn? I'm confused by the distinction between "play" on Deep One Rising's card and "put into play" on Hydra's card.

Is it possible to sacrifice Deep One Rising for Cthulhu and then bring it back into play with Hydra to destroy an opponent's character every turn? I'm confused by the distinction between "play" on Deep One Rising's card and "put into play" on Hydra's card.

As you probably already suspected, it does not work, because Deep One Rising's effect triggers when it is played, not when it is put into play. To 'play' means to pay its cost in your operations phase. To 'put into play' means you don't have to pay its cost and it can enter play at any time.

Dammit jhaelen, you spoil all my fun