I'm very curious to see what happens since I can't even find the manga to read, the wiki doesn't say. I have a feeling [RPG Real Estate] she'll either be saved/revived fairly quickly, or will be resurrected later. The episode showed her drop the necklace thing, but also the back cover artwork of volume 4 of the manga shows Kotone with the rest plus the new girl. So even if she actually dies, I have a feeling that she's resurrected later on. I don't think the series will likely get a second season, but even if it does, it will probably take 2 years or so since this goes up to the end of vol 3, so it'll take until vol 6 most likely to have the material for a second season. Feel free to correct me if I'm mistaken about it.