Are nephilim something that I can write about? There is another book I have read that has nephilim (Mortal Instruments), and I'm worried that people will think I copied that idea. The stories are very different, I'd like to think, but will people still draw connections? Please help me out here!
I really think that only having something similar to another book is not enought to say that you "copied" it. Some people will probably think so, but if the stories are really different, most people wont. There'll always be somebody that just wants to complain about something, even if there's nothing to complain about XP
Anyways, I think you should write it! I like nephilim… they are very interesting~
Go for it! As long as your plot and characters are different, there's no harm in it.
drawing on other authors as inspiration and being able to make connections between works isn't always a bad thing, as long as it's not directly plagiarism. if you're writing about angel-blooded teenagers who hunt demons and have accords with vampires and werewolves, then yes, that's bad. but if your idea is completely different, no one is going to think you copied. the idea of "nephilim" wasn't invented by cassandra clare, so no one can accuse you of plagiarism. (the term "nephilim" comes directly from the bible, so no one would think you're copying her.)
Glad @Cami pointed out nephilim come from the bible. Just wanted to pop in and say one of the most common pop culture references to nephalem (spelled differently literally every time I see it, so have fun with that!) is Blizzard's Diablo series, in which the protagonist is a nephalem protecting the human world from a war raging on between angels and demons.
I say go for it – it's common enough that most won't think you're copying anything, rare enough that most won't have any reference to compare to. Just make it your own and run with it!
Thanks everyone! Your answers are very encouraging, and I hope to start developing the plot and writing the book soon. I've been studying parts of the Bible to help too, so wish me luck!
Luck!