The Series
- In Memoriam: The final episode of Season 2."In Memory of our Friend Karen Powell."
- Similarly Named Works: The Hollow shares a name with a 1951 play by Agatha Christie, a 2004 teen horror movie, and a 2016 crime drama.
- Those Two Actors: Ashleigh Ball (Mira) and Nicole Oliver (the ironwood tree) both appeared in My Little Pony: Friendship Is Magic' and Littlest Pet Shop (2012).
- Word of God: Executive producer Josh Mepham confirmed on his twitter feed that Adam, Mira, and Kai are sixteen, fifteen, and fourteen years old respectively.