I recently attended the Roaring Lambs Christian writer's conference in Texas. I was fortunate enough to attend Mary DeMuth's session on fiction writing.
Mary said many interesting things, but one stuck for me. I did not record the exact quotation, but here is a summation. In your writing, it is okay for darkness to be dark, because that is how we know how brightly God's grace and redemption shine.
She credited J.R.R. Tolkien with this concept, quoting from the movie Return of the King when Sam compares the quest to the great stories and wonders how anything could be good again after so much bad had happened. I believe Samwise says much the same thing in the book, although that particular quote might have been said in The Two Towers.
I am familiar with Tolkien's concept of eucatastrophe, the wonderful, miraculous event that follows and redeems the darkest, most horrible event. He illustrates it best in The Return of the King when the black ships bring Aragorn instead of Sauron's armies. God illustrated it best when He raised Jesus from the dead, surely the most wonderful, miraculous event ever witnessed.
I love happy endings. I do not mind cheering my hero through trial after trial (or putting my hero through trial after trial, for that matter) if I believe he will win his goal. I, like Star Trek's Captain Kirk, do not believe in the no-win scenario. My hero's motto must be that of Galaxy Quest's Peter Quincy Taggert: "Never give up, never surrender." I want my evil evil, but I want my good to triumph. The darkest night must lead to the brightest dawn.
This may be an American worldview, or a Star Trek worldview, or dare I say a Christian worldview that refuses to accept that evil will win forever. Evil may win for a while, but not forever.
So, chins up, my friends. Fight the good fight, whether real or imagined. Bloody, battered good will triumph, and evil will be defeated.
In my books, anyway.