DC Comics is thought of as having more wholesome, traditionally heroic characters but it's also known for massacres like the killings at Sanctuary and the death of Green Lantern's Coast City. These events defined heroes and marked pivotal points in their publication history. Though some of these massacres were the result of natural disasters, others involved arduous battles between good and evil.
Source:https://www.cbr.com/biggest-killings-dc-comics/