Zane was the first writer to use the power of the lake to try to bring back his wife Barbara. As we know, what came back wasn't Barbara, but the dark presence wearing Barbara's face. The presence now had an external way to leave the lake and try to make itself larger and escape the "limitations" of the lake. To do this, it needed writers/artists/etc to use their imagination in order break free.
When Tom found out that his wife wasn't Barbara, he cut out her heart, which to him was full of darkness, and jumped into the lake, in his suit, to be the presence of light for anybody else fighting the dark presence (I know this is all speculation, but it makes sense to me). There was always balance, since the darkness escaped the lake, Tom was the balance in going into the lake; he was also the light to Barbara's dark.
Barbara kidnapped Alice to manipulated Alan into writing a story in which the dark presence was able to leave and be free, but Tom used his light to wake alan up from writing it and set him on his path. With the help of Cynthia Weaver, Tom left clues and helped Alan on his way. (Don't know if Tom created Cynthia Weaver or just manipulated her, but she doesn't seem to like him for putting her in the position of Lamp Lady) As the game tells us, Alan, along with Tom and Cynthia's help, "defeated" the presence with the clicker.
Now Tom shows up to talk to Alan...yada, yada, yada...he gets Mr. Scratch to take the place of Alan and he stays behind in the darkness to finish his book.
NOW, here are the two conclusion that I'm stuck on:
1) Alan was a real person who gets lured to Bright Falls by Dr Hartman/Dark Presence in order for him to write the story that will allow the dark presense to escape. Tom Zane, who sacrificed himself to stop his on creation (barbara) from escaping, helps Alan along the way to finish the story that he started (alan says that Tom was mistaken to make it a happily ever after story, there had to be balance). Alan swaps places with his wife, again the balance, and he finishes his book.
OR
2) Alan was a creation of Zane's all along. Zane made a mistake in trying to bring his wife back and accidentally created Barbara-Darkness that now wants to escape. Since he sacrificed himself to be the light in the darkness, he needed a way to stop Barbara. Since he had to power to create her in the first place, he needed another creation to stop her. So he created Alan to do just that. The evidence that I think supports this view is the clicker. HOW would Tom know about the clicker from Alan's past? HOW would he know the future and know that Alan needed the clicker to stop Barbara? It just doens't fit, unless Tom can see the future, but I doubt that.
Sorry, rant over, this amazing game just makes you think