IRON HEART, ANCIENT SOUL

"I've watched empires crumble to dust, Stark. You really think a few missiles scare me?"
For three thousand years, Y/N has walked the earth in secret. She is an ancient, incredibly powerful immortal capable of manipulating cosmic energy. To the rest of the world, she doesn't exist. To Nick Fury, she is S.H.I.E.L.D.'s ultimate hidden asset.
Her newest undercover mission? Go deep into the civilian world and act as the personal assistant to Tony Stark-the world's most chaotic, arrogant, and brilliant tech billionaire.
Tony doesn't know anything about S.H.I.E.L.D. He certainly doesn't know that his highly efficient, flawlessly organized new assistant has fought alongside gods and kings. He just thinks she's a sharp MIT graduate who makes a perfect cup of coffee and refuses to laugh at his jokes.
But as Tony sets out to build the first Iron Man armor, the lines between her mission and her emotions begin to blur. Can an ancient being who has sworn off human attachment survive being the sole anchor for a man changing the world?
No Pepper Potts. Just Tony Stark and an immortal assistant trying to survive the dawn of heroes.