Not addressing the issues in order, but:
1. The idea of having downsides, foreseen or not, to immortality is what Part 2 is all about. I want to devote the second half of this thing to exploring the character's difficulties either in maintaining or dealing with their own immortality.
2. While straight regeneration is something I had considered when outlining this, I figured to roll in the not-natural kind (i.e. not something like a
Troll) into the External Methods, thereby implying a "hungry" immortality that must be constantly upkept in order to continue existing.
3. In order to simplify the whole thing, I wanted to ignore uncountable threats like violence and simply focus on what would happen to a person who managed to obtain immortality without major hurdles. I wanted, in a sense, to compare and contrast the different methods of gaining immortality.
4. As for degradation over time, that is why I separated the chapters into the sections as I did.
- The Self is where the entire being would be upkept in an "ideal immortal" situation, where the downsides are generally dealing with being an immortal among mortals, rather than needing to worry about losing part of yourself.
- The Corporeal deals with making an immortal body at the expense of the mind, spirit, or both. It was low-hanging fruit, but I outlined the consequence of Lichdom to be the rotting of the body and possible descent into insanity.
- The Immaterial deals with ways of achieving immortality that doesn't involve the body. There's probably more there than I tapped into, but the issue of degradation probably isn't as pressing as the other issues these methods present.
5. The following thoughts I had in a half-hour break between when I wrote the above and now. I'm wondering if I should make each chapter an anthology of sorts, or perhaps do away with the chapter numbers for now in order to fit in more stories per concept. For instance, a story for chapter 1 about Raef would be very different than a story for chapter 1 about Denna (hypothetically speaking). The consequences Raef has to face are completely different as an angel than those Denna has to face as a treefolk.