“ 'Binding the Life Coil' is an ancient quasi-mystical technique rediscovered to prolong one's life at the expense of one reproductive ability. It is a simple magikal technique that anyone can learn (a skill or feat). The promise of near immortality or a lifespan of a thousand years or more makes everyone want to learn it.
This technique has a price though, the amount of immortality is in direct response to the strength of ones reproductive spirit. Those that have never breed will live longer than those that have. The use of the technique makes conception difficult, if not impossible. So you trade the future of your society for the chance for you to see much of that future.”
“ What if a invisible person could see other invisible creatures? All you would need to do to check for nasties hiding around is turn invisible.”
“ Pick up a pathology/microbiology book, and add the diseases/syndroms to your game. Your players will freak out.
Coughed at? Diphteria. or tuberculosis?
Drunk from a muddy stream? Or just walked through? Well, let us introduce you to schistosomiasis...
Hit by a stream of energy? Too moch mana is ust like too much radioactivity - perhaps all mages could develop cancer early if too powerful...”