White Walkers are ancient ice creatures threatening GOT. The undead army with unclear intentions is set to march over Westeros and cause disaster.
White Walkers speak in an ancient language called Skroth which sounds like the ice is crackling. Only White Walkers speak this language and no human has ever spoken it.
In the books, it is also written that the creatures like White Walkers can laugh even after they speak in ice crackling sound language.
The White Walkers King called as Night King was once a human being and was told as one of the first men.
There are only two ways to kill the immortal White Walkers as widely believed that they can be killed by fire.
However, fire one is not true the White Walkers can only be killed either by Dragonglass (as shown by Sam). Valyrian Steel can also kill these creatures.
White Walkers are significantly stronger than humans as one hit from a White Walker can kill a human.
White Walkers possess magical powers as they can freeze anything they touch. As their King can also change any human into White Walker.
Humans can often tell that White Walkers are coming due to drastic drops in temperatures. The drop in temperature occurs due to their magical power of freezing.