I have not done this but some deckbuilding I've seen has incorporated cards from 2 core sets. For instance, each core set comes with 2xForest Snare. I've heard of decks with 3xForest Snare. I was under the impression that decks should be constructed using the cards supplied in a single core set and single sets of the Adventure Packs.

Is it OK to build decks by combining multiple sets or was it intended to build decks from single sets and APs?

You can build your own decks in any way that you like. If you want to combine 2 or even 3 core sets, you can. If you want to add or not add AP cards, you can. The only restrictions are that you have a maximum of 3 copies of each card and the decks should be 50 cards, not counting the heros. Some people do play with 30 or 40 card decks but the official number is 50. Note though, that you do not combine encounter decks from multiple core sets.

Titan said:

i agree, although i read that it is a minimum of 50 cards, although most dont go over 60

Thanks for the replies! I'm new to the LCG scene and I'm kinda against buying redundant sets. I prefer to build without buying extra. I'll see how that works but it seemed to me that the point of the LCG wasn't to chase cards for powerdecks. Although, playing through the core quests has proven quite challenging which makes a good game great.

Just my opinion. For those that are building from redundant sets, carry on! As long as we're all enjoying what we do