Oops! Yup, you're right. It was Fang of Ir Yut I ascended because I don't have Fatebringer & Atheon's Epilogue I ascended because I don't have Word of Crota. I decided not to bother ascending Abyss Defiant because I've got an ascended Vex Mythoclast so I figured it was better to go with that since it saves me an Etheric Light.