Twilight and Pinkie come across a stallion who's in a pretty bad mood. After explaining he feels lonely, and in need of things to do, he gets to help out the mane six with various tasks in their everyday life.
He grows close enough to them that he gets to join them on their adventures, and he even becomes an honorary Element of Harmony.
A rejection, a change of heart, and some relationship issues later, he marries the pony he had a crush on since they first met, and they live happily together, though, many issues still pop up, both for Equestria, and their relationship.
Chapters (2)
Why does the word Element in the story’s title have six quotation marks around it?
So he got his cutie mark by crashing into things?
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It wasn't exactly crashing into things
I will go more into his backstory in a later chapter
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Later on he gets treated like an Element of Harmony, even getting a necklace made to look like the others, but he never actually becomes one.