I'll try to keep this short and sweet.
Sometimes, there is 'bad language.' While I myself live by a certain standard regarding expletives, other characters and people do not - and since I believe in being true to characters (I didn't invent them, after all), I try to write them consistently with how they've been originally designed. If they swear, then they swear. If it makes you unhappy, then you should find another fandom.
Sometimes, there is violence. Hey - even the Bible has violence of all kinds in it; I try not to be too gratutitous, but don't be surprised if you come across it when it's important to a storyline.
Sometimes, there is religion. The good-vs.-evil dynamic is one that is very important to me personally - and thus, you'll find it embedded in pretty much everything I write. You'll also find occasional references to God and *gasp* an idea of an objective morality. If you're looking for humanistic meaninglessness that will leave you depressed, these really aren't the fics for you.
Sometimes, there is sex. Well, not sex per se; I refuse to write 'lemons.' There will, however, be references to it, as sometimes it DOES happen in the course of a person's life (clearly, or none of us would be here). Often, such an incident is very important to the plot - hence the reference. Don't be shocked if somebody somewhere actually mentions it in passing.
Sometimes, there are spoilers. Whenever I read or watch an update to a series, I tend to incorporate what I've learned. After all, it's someone else's world; while I thoroughly enjoy playing in it, I'm not going to try to change the world they created too much. I wouldn't want them to change mine, either.
That's it for the warnings. Read and enjoy!