In the dawn of man, a million years ago (According to a Kid Eternity-story, not actual sceintific evidence. Though, in Kid Eternitys universe, humans came to existence far sooner, it seems), a man was killed by a brute.
He was to spend the remainder of his eternal life in Eternity, but due to some kind of confusion at the time, his name wasn`t written down to the book of Eternity, containing the name of everyone who has died.
He came back to life, or something.
For a million years, this man walked the Earth. He wanted to rule it.
He persuaded and inspired many now great, historic persons to conquer for him. Alexander the Great, Hitler...
When Mr. Keeper was doing his checking of the book of Eternity (that is to be done every million years), he noticed that an error had happened a thousand millenia ago.
Kid and Keep went to Earth, to defeat him. The man aimed to take over Africa.
Series of fights took place. Historical men were called out to help. All that stuff.
At the end of the story, Kid called for the brutish, ancient ancestor of man, who had killed the long lived man.
And killed him again. This time, to surely be marked down to the book.