Scipio243
the main character is a 'Phantom' and is already dead, so cannot die. Instead, the enemy is rapidly weakening him with this sickness which prevents the luxury we all know as sleep.
Question: Why does your main character need to sleep? He's already dead, so why would he need to engage in the act of sleeping, which is a way for the physical body to regain its strength?
Not trying to bash of flame, dear, just curious as to how that works.
As for your other question, I've used illness a few times. It's more used as a tool to explain certain events, though. For instance, the sickness I use in my current projects only attacks mages--there's something about their physical makeup that differs from regular people. So, naturally, people who get it are exposed as mages. It was also an epidemic that wiped out a third of a nation's population, which of course gave other countries reason to dislike the first nation.
I'm a fan of persecution and mass genocied in my stories--what can I say?