Emmet, Mandy's deceased father, walked her down the aisle. He wasn't a zombie, or even a ghost. Shelly had never heard of the dead being resurrected in any other way, and she didn't understand how he could be here, until she heard Shlee tell Sheldon.
"Gaia contacted the angel Amenadiel, and told him that he owed your family for what he did to your sister." Shlee's voice was soft, and Shelly had to strain to hear her over the music. "Gaia formed him a body, and his spirit is inhabiting it. He has to return after the wedding."
A sob pulled Shelly's attention back to the audience, where she was surprised to see Alloria smiling at her late… He wasn't her husband, and by all accounts she knew, Alloria hated Emmet. They both loved their daughter, though. And when Emmet's eyes fell on the last living elf, Shelly saw kindness and warmth aimed at the woman. Perhaps there wasn't as much vitriol as she was led to believe between the two.