Normal people: carriers of mostly unpalatable souls
Kyuubey: eater of delicious souls
Magical girls: greedy and evil people who agree to have their souls moved outside of their bodies
Witches: greedy and evil magical girls whose soul gems have become very dark and palatable indeed
Kyuubey eats souls, even has them brought to him, by making magical girls hunt witches for Grief Seeds. It is important to me that he does not (can not) eat Soul Gems or normal souls. He wants the tainted, evil ones. Possibly when he eats them he is actually relaying them to hell through a little gate on his back.
The whole thing suggests that Kyuubey is literally talking out of his ass or something lololololl. His "face" is clearly just a fake thing to keep the young women he targets from running away terrified.
WALPURGIS NIGHT
(A thing depicted in Faust, I guess I'm going to have to read that in more detail)
or
SHIT GETS REAL NEXT EPISODE
Walpurgis night is probably the stuff depicted at the beginning of the first episode. Homura has told Anko she has a way of dealing with Sayaka (and thus with Walpurgis night), so she likely knows that Sayaka will be turned into a witch, and she plans to fight and kill Sayaka without Madoka ever knowing to prevent Madoka from turning into a magical girl. She may leave Madoka in some relatively safe place, maybe even outside of the witch dimension. Kyuubey, seeing his chance, will suggest that he help Madoka wander Sayaka's witch dimension to try and find her friends. She will do just that and emerge at exactly the wrong time and discover her friends trying to kill each other. Kyuubey will then tell Madoka to "help" by becoming a magical girl, and since Homura is busy trying not to get killed by Sayaka, even desperately screaming at Madoka is a possibly deadly mistake for her---not that Madoka could hear her anyway. So Madoka will make her wish, terrible things will happen, and either many things will be revealed leading straight up to the last boss, or we will rewind to episode one and see everything happen again from Homura's point of view. Or Madoka's, with HORRIBLE ENDLESS IRONY.
On the subject of Anko: Anko has more than one soul gem, one of which she took from a magical girl she killed (or who flopped over and died without her SOUL). She has probably done this at least once before, and when the extra soul gem ran out she tossed it over her shoulder and moved on to killing the next magical girl. She is understandably just a little disturbed when she finds out that she was kind of eating other people's souls and leaving their bodies to be corpses, shells, or, as she puts it, "zombies." What happened, Anko?
This may also indicate that Anko believes that tainted soul gems eventually become grief seeds. She's horrified to learn that the witches she so happily farmed and killed were actually human souls once. Then again she wasn't really worried about familiars killing people, so I dunno. I guess for Anko there would have to be a difference between that and actively consuming those people herself.
Anko is dark red and has a name that sounds like bean paste, and she constantly munches sweet junk food (so far we have wafers or waffles, taiyaki, and POCKY). I find it hard to believe that this characterization does not have some good in it. There is plenty of room for her to see the error of her ways and join the magical girl team. Of course, then she will insist on fighting Sayaka (possibly after winking at Madoka) and die, and then Madoka will be horrified. Or she'll decide that she'd rather not help, Homura will kill her on the spot and head into Sayaka's witch dimension, and Madoka will be horrified.
I've known for a long time, I just didn't know how to translate it (and still don't) so I didn't bother putting it in my journal. Madoka's last name, Kaname, is a homonym for the word meaning pivot, cornerstone, requirement. Madoka means a circle. HMMMM. Also, if you read the character for "madoka" a different way, it becomes "en", which is another way to read both characters that can be read as "homura."
円(まどか) → 円(えん) → 焔(えん) → 焔(ほむら)
I didn't write about it here yet, but I imagine a possibility of Madoka actually becoming Homura. Yeah, I dunno. Right now that also seems more plausible than whatever I think about that black cat, just because we don't know ANYTHING about the cat.