This occurs during the first half of Blondebolt's Journal, when Blondebolt was trying to use magic.
His futile attempts resulted in nothing, and Blondebolt gave up.
He did succeed at his research on Unicorn magic though, and he went to be the student of Celestia for his superb scientific mind.
After many long years, he became a lead scientist in an attempt to make a device to take the ponies to other universes.
They succeeded, and ponies became the primary intelligent life in all of existence.
He lived the rest of his life, blissfully unaware of what he had been, happy at home with Fable, who was happy with him.
Seka eventually recovered, and became a good friend with Blondebolt.
When both of them passed away on the same day, he accepted it, and continued his pursuits, his heart never leaving them for a moment.
In the end, he lived to be a hundred and twenty, the longest any pony ever lived.
It is said, that in death, he finally met Knifer, and the two now happily frolic through the fields of the afterlife with Fable and Seka, in a form of a happy family.