Okay, taking it from the top.
Hi, I'm Auric Fulcrum, also known as Frank DeFontaine. For about 1,500 years, I wasn't alive. I instead inhabited my Dullahan costume as a spirit because of my sword, which also brought me to Equestria. Once I got here, after a few years of back and forth, Sunbutt imprisoned me because of a minor misunderstanding.
I heard that!
You were meant to!
Anyways, once I got out, I learned that the Wise One was coming to this reality, so I did what came natural to me.
I sought out the power of the Golden Sun and used it to defeat him so utterly I would never have to worry about him again.
Problem was, the energies that bound me together and the power of the Sun conflicted, so my armor fell apart. And without the armor, I was unbound, unfocused.
I came to a week later in the same basement I had been imprisoned, in my old body, but with a few...upgrades. Like Alchemy being a Thing I can Do.
Now that I'm alive again, my to-do list is radically different, but no less daunting.
For starters, how am I supposed to stop a mountain from sinking into the earth?!
Most people wouldn't think dressing up as an optional boss would land them in Equestria. Most people would be right. Most people aren't me. Most people still have their bloody head!
Defating foes from Beyond? Easy enough. Making Celly see where her mistakes lie? No problem. Being torn apart and reborn because of the Golden Sun? Okay, that one, I admit, knocked me for a loop.
Okay, saving Equestria from powers I foisted on it, not a problem. Saving a mare from certain death, easy! Getting used to being a pony? Someone shoot me.
Because every so often, even in a new world, an immortal likes to look back on what was, and remember...