To add a little fuel to the Hop-Pop may die theory.
Grime who is Sasha's toad dad at this point saves her at the end of S1.
Andrias(bitch ass) who was possibly a father figure to Marcy literally back stabed her at the end of S2.
So thats two father figures evolved with saving/ending their charges lives. So applying that to the rule of three.
Hop-Pop who is essentially Anne's grand father might sacrifice himself for her or be envoled with saving her life at the end of S3. Something like that.
Hopefully some of this makes sense