recthething | SPN Fic Rec: Eldest Daughter, First-Born Son (Dean/Cassie)

I just finished reading this fic and it's so good, it deserves more love! Creator chose not to warn, and I think that's because of the unhealthy relationship between Dean and John, but no archive warnings apply. It does have a bittersweet/somewhat sad ending because it matches up with the canon story of Dean/Cassie but gives so much wonderful backstory. Dean is trans in this, but I love how much of canon still fits so well. Plus I think the author nails the weird way Dean & John interact, given Sam's absence.

eldest daughter, first-born son (13836 words) by adastreia
Fandom: Supernatural (TV 2005)
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Relationships: Cassie Robinson/Dean Winchester, Dean Winchester & John Winchester
Additional Tags: Pre-Canon, Getting Together, Developing Relationship, Trans Dean Winchester, Cunnilingus, Vaginal Fingering, Bittersweet Ending, Sam Winchester Present As Absence, Canon-Typical Casual Alcoholism, Additional Warnings In Author's Note, Casefic as in a Case is Also Happening During the Events of the Fic, Angst and Fluff and Smut
Summary:

Dean meets Cassie when Sam has been gone for 1 year and 8 months. He’s been doing that lately, measuring time in Sam’s absence. Like life ended and started between his little brother shoving his few possessions in a duffel bag and taking off to the local bus station.