Warner Bros.

When Harry first saw Thestrals when he returned to Hogwarts in his fifth year, he was not sure if he was the only one who could see them. However, both Neville Longbottom and Luna Lovegood were able to see them as well because only people who have seen death are able to see the Thestrals. Seeing death, especially a tragic one, as in Harry’s case when he witnessed Cedric Diggory being murdered in front of him, can change a person. People who experience such awful traumas, such as survivors of gun violence and other tragedies, often might feel alone and unable to emotionally relate to others. By finding other people with similar experiences, survivors of such tragedies may find some comfort in feeling less alone and being able to discuss and process their experiences.