I cannot stress how important this is.
If I’m reading a book and the main character or even support characters aren’t affected by the death of a group mate/ close character I lose interest. Not because it is bad writing… just because it doesn’t reflect the main characters relationship. If you spent the majority of the book or books building a relationship with a character that is then killed off that main character – if they had been a real person – would react.
This doesn’t just cover killed off characters. A character can be badly hurt, captured… what have you and if the main character doesn’t react to the situation you’ve lost me. Sorry but unless your main character is a heartless robot who doesn’t give two bulls about anything, then your character must show some emotions.
A good example of using a death to motivate the main character is Katniss and Rue from the Hunger Games. My Gods that was a great way to use death to motivate and Katniss’s reaction was natural. Rue’s death pushed Katniss to beat the game, defy Snow, and in the end led to the whole rebellion. Rue set the fire and Katniss let it burn until it couldn’t be contained by the Capital any longer.
I’m sure there are other great examples of death and motivation out there but KatRue just stood out in my mind.
So, yeah… moral of this rant – make sure your main character reacts to the death of an innocent character…