(Nico's viewpoint)
Chapter 3.5: A Brief Summary of a Dark Past.
Okay, about what happened between Faye, Marceline, and I. It's a long story, but I'll try to make it quick...
My parents were far from my house at the time, I believed that an ancient amulet of seven Elemental Powers cursed me with Immortality (in hindsight, it was actually hereditary and I didn't understand at the time.), I fell in love with Marceline, we made it official that we were going steady on my 809th birthday, Marceline gave me Vampirism so we were able to stay together (her father, Hunson, was insidiously discriminatory toward non-Vampires, and was curious about how my soul tasted. Creep.), I met new people who were exactly like me, I started wizardry training again, Marceline joined me in wizardry training, I started tutoring Marceline in Shadow Travel, she passed through my shadow into the land of Yyy, Faye possessed her, Marceline's soul was trapped in Yyy, Faye wreaked havoc across Ooo, I found a strange altar made of mythrite and dragon bone, Marceline got killed, I placed my seven-point amulet in an empty hollow in the altar (which needed ten amulets altogether), I took on the form of a serpentine dragon while my body was being encased in mythrite, I became The Dragon of Creation, my friends arrived at the scene of the battle, I resurrected Marceline, Marceline, my friends, and my draconic avatar then destroyed Faye. Or so we thought.
...So that's the summary of what had happened and then some.