The practice of human sacrifice is as ancient as human civilization and has been practiced variously by various cultures, but most often to pacify gods or nature in the same manner of animal sacrifices. For example, maidens being tossed into volcanoes to keep them from erupting, or victims being buried at the foundations of castles, temples or bridges to protect the constructions from ruin.
We're way past human sacrifice now, of course, but fictional character sacrifice? Today's super-comics creators seem rather devoted to that particular ritual, with many an "event" story arc beginning with the death of a character, as if they were being sacrificed to bless the ensuing narrative.
The latest example is DC Comics' three-book Trinity War crossover, which begins in earnest this week but has been slowly ramping up in several books, most notably Justice League of America, where one of the publisher's oldest and best-known characters was seemingly killed recently.
Be warned, for below there are spoilers for stories as old as 2004's Identity Crisis and as recent as Justice League of America #5.