I'm running the lost mine of Phandelver and during the first session, the party bribed and then befriended a goblin. The goblin was super helpful during the first major dungeon, but eventually wound up without a head. One of my players rolled a nat 20 investigation on the corpse after specifically stating that he was looking for information about his next of kin. I made some stuff up about a photo of / letter from his wife and kid.

I'm prepping for the next session, and there's a captured goblin in this likely next hideout. This feels like an obvious place to put his wife - saying she was captured as retribution for her husband turning on the baddies.

I started thinking ahead and wanted to do something interesting with the young son, and it occurred to me to have him be captured by a hag when he was left to fend for himself.

I'm a new DM and I'm wondering if anyone has any advice for handling this encounter and scenario. Is there anything anywhere about non-human hagspawn (either official or homebrew?). I'm fine to wing it if needed, but if there's something out there offering guidance, I'd love to look it over. Short of that, if anyone has any advice or cool ideas, please let me know.