RandV
It's a wolf v2.0
Do we know anything about the White Walker's motivations? Do we even know anything about their goals? I hate that the show's big bad guys are apparently evil for evil's sake. I hope we get some insight into why they've decided to re-emerge thousands of years after being defeated.
Well the show has shown us that the Children of the Forest created them as a last resort weapon to destroy humanity. Don't remember specifically what lore the show has given beyond that, though the season 1 or season 2 DVD sets had some extra features with Bran narrating the history, but it's pretty obvious that humanity won that initially war thousands of years ago, then built 'The Wall' and established the order of the Nights Watch to guard against them.
So you can extrapolate from this that the white walkers were defeated, but never fully destroyed. Now for whatever reason they have recently re-emerged from whatever prison held them, and are looking to break the wall and get back to business.