[Havelock]

Originally Posted by Khorum

The Others, which hadn't been sighted in centuries, reappeared in the prologue at the beginning of the series. The Others are obviously magical, mythical creatures that even men of the Nightwatch had some difficulty believing until they confronted them. The return of the Others, and the long winter that's coming (along with the return of magic and several associated prophecies) seems to be the central sweeping arc of ASoIAF.

Yes, even the red priests of Braavos mention that their magic is returning. Yes, the return of the dragons is repeatedly hinted at as the source of resurgent magic, but the dragons came from inert fossilized eggs that were brought to life BY magic, and NOT by a trained magic user either (Dany pretty much just winged it). Before the dragons had been hatched, The Others had turned a clan of wildlings and a couple Night Watch into zombies, Drogo had been murdered by sorcery, various Starks were manifesting as changelings, and magic had turned some decorative dragon fossils into living eggs, literally an chicken-or-egg paradox in itself.

Martin has made the dragons the OBVIOUS source of magic, which is a red flag in this series, where anything obvious usually ends up on a pike and dipped in tar. The early chapter previews of ADwD even hint that the three dragons themselves aren't safe. A Song of Ice and Fire -> A Dance with Dragons These are transcripts by GRRM's readings from the next book.. the Daenerys chapter hints at one of the dragons' fate.

Here's one thing I'm wondering about the Others: did Mance begin searching for the Horn because the Others were raising a fuss, or did he start looking for the Horn because he wanted to head south? If it's the latter, his searching all the graves could have been what triggered the resurgence of the Others.