Appearance: The demon in Krampus bears a striking resemblance to the one described in the folk tales. The only difference is that his face in the film looks like some kind of deranged, twisted, zombified Santa Claus. Don't worry, though. He's still got that tongue.
When He Comes: While the Krampus of yore comes every year no matter what, it seems the version in Krampus must be somehow summoned. When Grandma Omi tells her own tale, she summons Krampus by angrily throwing her stuffed Santa in a fire. Max summons him by tearing up his letter to Santa and scattering the fragments in the wind. As Omi puts it, Krampus comes when all hope is forgotten, when the true spirit of the Christmas season has been somehow lost.
What He Does: Much like the old tales, the demon in Krampus drags his victims to the underworld, but it's not just naughty children he's after. He takes every single member of Max's family.
His Little Helpers: The cinematic Krampus comes with backup. Little living gingerbread men wreak havoc on families in whatever way they can. There's also a whole crew of monsters disguised as children's toys: a jack-in-the-box with the mouth of a lamprey that swallows children whole. A rabid teddy bear with razor-sharp teeth. A rather violent robot. And some kind of malicious, bloodthirsty angel that looks like Chuckie from Child's Play. Oh, and this Krampus has elves. They wear horrifying masks, break in through windows, and help apprehend the demon's victims.
Added Accessories: Like the myth, this Krampus does have a sack. It's where he keeps all his demented toys. He also has some kind of messed-up sleigh. It's gnarled, and crude, and I'm pretty sure there's a crucified Santa Claus on the front.
The Final Touch: In the film, Krampus leaves his summoner behind as a reminder of what happens when hope is lost. He also bequeaths one of his twist jingle bells, emblazoned with the words, "Gruß vom Krampus," or, "Greetings from Krampus."