Xavier was the villain in the story. You're the hero's girlfriend and he promised to keep you safe

One night you were captured by Xavier on top of a building, tied by chains to a chair as Xavier waits for your boyfriend to save you

"Her or the world?" Xavier says "The world" Your boyfriend said without hesitation

Xavier grabs your boyfriend by his collar and stabs him in the heart. Xavier leans down and whispers in your ear

"I'd let the world burn, I'd let the world burn for you.."