Canon Fodder: character class. The rather-detailed characters who you are introduced to in a few paragraphs before they die, usually senselessly, randomly, messily and/or cruelly, often to establish some sense of connection to the individual casualties in a steadily-mounting body count. Often found in the horror genre. Canon fodder characters come in a few distinct types:
They Deserved It, Really -- Cosmic justice is visited upon these characters with a swift and often gory hand. They are the scum of the earth. They needed killin', and you might even be semi-glad they're dead, but the forces that got them will probably kill again, and this time it might be
Someone We Should Care About -- Often heroic, or too-good-to-be-true. Little girls, heroic emergency workers, good, decent people. They are often sacrificed so the readers will know that This Villain Is Hardcore Bad. (Cedric Diggory would be a prime example of this, but we're introduced to him well before he actually does die.)
Random Bystanders -- Wrong place, wrong time. Decent but flawed people die when hell-demons, crazed cults, Dark Lords, and other nasties decide to go on a killing spree.