Sectarian violence among Christians happens when people who are Christian disagree so strongly that they fight or argue with each other. This can be from different Christian groups, like Catholic or Protestant, that don't see eye-to-eye on their beliefs. Sometimes people who are of different Christian groups also have trouble getting along because of their political views, which can lead to violence. This can be a very scary and dangerous thing that can lead to hurt feelings, property damage, and even death of innocent people.