"Kill your darlings" only applies if you're holding onto something that actually hurts your story. But jerks sometimes use "kill your darlings" as a weapon to try to break you. Don't wantonly kill what you love the most about your story. That's why you're writing it. Make it work.
Yes. To put it in a historical context, cavemen wouldn't indiscriminately kill their children. They loved their children! They would only kill Derrick, whose cries were attracting rabid angry mammoths and sabretooth tigers.
I see what you're saying, but that's not Kill Your Darlings. Darlings are scenes, not characters.
Derrick gets to live, he just gets all his dialogue left in the Cutting Room.
Darlings CAN be characters. You might be fond of a character, they might be an expression of something you value, but if they don't contribute anything to the story (which might be difficult to realise), they need to go (or maybe merged with another character).
