If you're here because Apollo just entered the story - nothing tragic happens with him. It's not a source of sadness. He eventually goes to live with the family of a friend, and has a very long and happy life. It's mentioned in a sort of "where are they now?" epilogue that he eventually passed away of old age.
The comic does not depict anything along the lines of anorexia or bulimia, but some students are shown to develop major psychological issues surrounding food due to its scarcity and their limited meal times.
Joe has a severe PTSD flashback in one chapter. He suffers from PTSD after leaving Elan too. Healing from PTSD is a major theme in the post-Elan chapters.
Enforced by staff and students at Elan. In order for a student to rank up in the school's hierarchy and eventually graduate, they have to become abusive.
When chapter 77 was first released, it used an anti-Romani slur, but it has since been replaced. The author used the word out of ignorance, not malice.
Not organized religion but Joe discusses his belief in a force that he calls The Great Energy. It's more of a philosophy than a religion, but still worth noting.
The comic is a true story about a boarding school for "troubled teens." The students are abused physically, verbally, emotionally, and mentally. Very harrowing.