BOOK 1: Ha ha look it's a talking hat
BOOK 3: These spooky scary cloaked ghost guys can literally eat your soul. But they're literally made of Bad Mood so you can drive them away with a walking embodiment of distilled hope and happiness, which makes a lot of sense when you think about it. Go get 'em, kid.
BOOK 7: This is called the "resurrection stone" but the most it can do is bring back a ghostly image of the people you lost, for a little bit, so the most they can do is keep you company while you willingly walk towards the worst enemy of your entire people to get slaughtered, but to be perfectly frank that's the most anyone could do, and your companions might get killed with you, so you might as well have some companions who are already dead, don't worry we'll all be sure to thank you at the funeral.
EPILOGUE: Ha ha look it's a talking hat