Lots of fantasy takes place in incredibly dangerous worlds. Tyrants and dragons abound, villains and varlets are commonplace, and heroes (or anti-heroes) struggle to survive.
Or do they?
The questions of how many characters of importance to kill off and whether or not very major characters should be killed are not easy ones to answer.
Killing off a character brings their part in a story (usually) to a dramatic and permanent close, and can either make a story all the more enthralling or irritate the reader to a significant degree. Particularly in series, killing characters can be something that writers are often loathe to do, as it permanently removes someone to whom the readership has hopefully become emotionally attached.
But, if the world is dangerous and the adversaries are deadly, how credible is it to have everyone survive with nothing but flesh wounds?
Credibility in fantasy can be tricky, as it often involves suspending disbelief when it comes to dragons and magic and elves. However, I think a key part of a believable fantasy world is having credible, realistic characters and people who survive every danger are incredible.
Killing off significant figures presents a great opportunity for writers as well as terminating (hopefully) entertaining characters. When major characters die it instils a sense of uncertainty about whether or not others will live and gives subsequent violent scenes a greater edge of danger.
It's important that death fits the story and isn't included purely for shock value. It has to at least make sense and be plausible, if not actually meaningful.
Sometimes a plot also demands that someone not wearing a red Star Trek uniform gets killed. War is the most obvious example, and because Bane of Souls revolves around one or more murderers I wanted to make sure that it didn't fall into the trap of having lots of murder victims but everyone connected with the plot/protagonist surviving.
I think it's also the case that a death can be a strong, character-defining moment. If the village idiot sacrifices his life to save a spoilt brat it can recast the idiot as a hero and set the brat on a new path.