The choice to kill off a beloved character is much like choosing to end a long-term relationship (be it a friendship or something with much deeper ties). It’s a gut wrenching decision, but sometimes it’s necessary to move the story forward.
I had to do that with one of my works in progress. I loved this character. He was funny, he brought life and laughter and confusion to my main characters… and he died. Not out of deliberate maliciousness, but because it was a purely selfless act on his part that was ultimately necessary. He did what no other character in my novel could do. And the story arc could continue as a result of his death.
I think the good writers can do that. Not that every one of us needs to kill off a character, but that willingness to sacrifice someone we’ve built (literally!) from the ground up in order to move forward separates us from those who believe every single person (and I use that word loosely, since not everyone qualifies as a ‘person’ when writing) must survive in order to have a viable storyline.
Death, ultimately, adds something to your novel. It brings life to the forefront. It makes you that much more invested in whatever quest or goal your main characters have. The bottom line is… if it’s too easy, if it doesn’t grip your heart, the journey just might not be worth reading to the end of the book.