In the most recent issue of Early Childhood Research and Practice, there is an interesting paper about aggression in children's stories. It is a good read - and it has me thinking about the stories my students are telling. About one-third of the stories collected for this study contained aggressive elements.
You can read the paper here.
Much of the dramatic play in our classroom (which goes on with a large group of children for the majority of the day, both indoors and out) includes charcters who die - often princesses - but I think that is as close to "aggression" in narratives as this group gets. But I am interested in observing more closely. The paper talks about the action verbs that describe aggressive acts that are about harming characters - hitting, eating, fighting, etc. I've definitely heard those, especially in the written and dictated stories over the dramatic play.