According to Lena, satyrs are the original party animals—except she thinks that "they liven up a party too much" (7.42). She even goes so far as to assert that the satyrs would be a bad influence on the kids, saying, "'Satyrs would only teach you bad manners. I think they invented them'" (7.46). The kids get to meet some satyrs anyway, though, when they go looking for Grandpa and Lena after Midsummer Eve. The first one they see looks like this:
From the waist up, he was a shirtless man with an exceptionally hairy chest and a pair of pointy horns above his forehead. From the waist down he had the legs of a shaggy goat. (11.207)
This one is Doren, and his redheaded buddy is named Newel. And even though they're annoyed at the kids for ruining their stew-stealing operation, they still help them escape from the hungry and irritated ogress. They craftily ask for some batteries, too, since they like watching television even though Grandpa's against having technology on the preserve.
But when the kids ask for help finding Grandpa and Lena, the satyrs get super-non-committal and say, "this is a bad week for us" (11.292), emphasizing that they have "Lots of commitments" (11.293). How many commitments can a handful of carefree satyrs have, though? Sounds like these dudes aren't evil or anything, but not always that helpful either. They're the bros of this book.