I know that Gonan's story was really short but it's not over. I'm going to make a continuation and call it the corpse gene. This will explain all questions about Gonan's strange family. There are different types of corpses too.
The next story will tell all about Gonan's encounters with his other siblings and will include how they died. It will show how the other types of corpses evolve and what they look like. You may have noticed that normal corpses transform with the pain of death. They must keep that pain until they come back to life.
Also I might mention that what Gonan said about killing corpses is not entirely true. There is one type of corpse is not entirely true. There is one type of corpse that can't survive without the loss of blood. It they didn't loose blood every day, they would probably explode like that girl from Cloverfield. Well, that's all until my next story.