A strikingly evocative and inspiring supplement! Tragic backstories seem like a dime a dozen, but the backgrounds included here are anything but trite. Most impressive are the features, which are a significant departure from the "Free food/shelter/contact" template used by many of the PHB backgrounds. My personal favourites is the Fallen background, which provides very interesting interactions with the world. In addition to these, the concepts and the suggested characteristics are specific enough to clue you in to the design intent, while the prompt leaves you with enough wiggle room to design your own. What any DM considering these needs to have in mind: a few of them put a significant burden on your world building (or knowledge of canon setting lore). The Fallen requires you to flesh out the position of supreme beings in your setting, and both Relic and Amnesiac demands that you consider details of ancient history and an unknown player backstory, respectively. Work with your players to share the load if you need to.

These are some great RP ideas, all faithfully in line with the core PHB. Having played characters based on these concepts before, I can say there are many great ideas in here i never thought of for my own characters. Definitely would allow these in my games as well. Jacob has great instincts for story and design both. One to keep an eye on!