Use the word bloodshed to mean people being killed or wounded, especially during a war. A strong dislike of bloodshed might keep a person from joining the military.
You can use the noun bloodshed to talk about any kind of violence: "My mom never let me play those video games when I was growing up, because of all the bloodshed." It's most commonly used to refer to the major side effect of war, the death and injury of many humans. Bloodshed dates from the 1500s, meaning "the shedding of one's blood" or "slaughter."