In the Season 8 episode “The Damned,” Rick (Andrew Lincoln) is ambushed by an unnamed Savior, one of the survivors under Negan’s (Jeffrey Dean Morgan) leadership. He sees a “Grace Be God” tattoo on the man’s chest and finds a key in the man’s pocket. The key unlocks the door to a nursery where a baby is lying in a crib, and the name “Gracie” is painted on the wall above.
Rick contemplates taking Gracie home with him in the next episode, but Aaron — who had just lost his boyfriend, Eric (Jordan Woods-Robinson) — says he can take the baby to the Hilltop Colony.
Aaron eventually adopts Gracie and starts raising her in the Alexandria Safe-Zone, where she grows up alongside Judith (Cailey Fleming), Rick’s adoptive daughter, and R.J. (Antony Azor), Rick’s son with Michonne (Danai Gurira).