A well-written piece should include your own ideas and creativity. Borrowing characters and scenarios from other games, movies, books, etc. is almost plagiarism.
I kind of agree with this. What makes it okay is the way they used it to make a good read. I'm full-on with originality, but I'm good as long as it satisfies me.
However if it's pretty much replicating the story and origins of the character taken, then that's where I draw the line.
Seems that my line is much further away than yours.