"A Song of Ice and Fire" series author George R R Martin hasn't commented on when his upcoming novel "The Winds of Winter" will be published, but that hasn't stopped fans from speculating what will unfold in the book.

One popular fan theory has it that the White Walkers will emerge as one of the biggest threats to humanity before "The Winds of Winter", the sixth book in the "A Song of Ice and Fire" series, concludes.

However, according to iDigital Times, for the White Walkers to become the ultimate threat, the Wall has to fall and human lives should be threatened. Several fans too believe that if the Others, or White Walkers, don't come south of the Wall, they "will have been built up for nothing."

A good number of fans also believe that this would be the perfect time to take advantage of the situation, as the Night's Watch is currently preoccupied with power struggle. "A Dance with Dragons" saw Jon Snow being stabbed to death by his Night's Watch comrades, and while it remains to be seen if he will be magically brought back to life, it can be assumed that at present there is a lot of confusion in the North.

If the White Walkers "can't take advantage of that situation then they are not enemies to be feared at all," wrote one fan. "Imagine the dragons which are essentially the nukes of this world, imagine they didn't do a single thing, didn't kill anybody, didn't raze a village, nothing. It would be like that but 10 times worse."

"The Winds of Winter" is expected to be released before season 6 of HBO's "Game of Thrones" airs, meaning the book could be out in the first half of 2016. In an April interview with Entertainment Weekly, Martin said that the upcoming instalment will contain a shocker that will drive fans crazy.

"This is going to drive your readers crazy," he teased, "but I love it. I'm still weighing whether to go that direction or not. It's a great twist. It's easy to do things that are shocking or unexpected, but they have to grow out of characters. They have to grow out of situations. Otherwise, it's just being shocking for being shocking."