@stray_dog_
Check chapter 68
The doll was already explained and was kind of self evident from when it first appeared (At least who it represented was).
Everyone sitting around the dinner table is Thistle's approximation of what life used to be like for him, and the people there (including the doll) are the royal family.
Derghal sits at the head of the table, his wife to his right, and to her right is their Grandson Yaad (The child from the village who explained their immortality and the winged lion).
To Derghal's left sit his son (The Puppet) Eodio and next to Eodio is his wife.
Thistle removed their souls from their bodies because they all started acting against him, their bodies are still alive and immortal though so sit at the table.
The puppet sits in Eodio's place because, as explained in chapter 68 by the winged lion (Though he's an established unreliable character), King Derghal used Eodio's body to climb to the surface and unveil the dungeon. This happened in flashback in chapter 1 with the "Defeat the mad sorcerer and become king of the dungeon!" thing. Derghal, being outside the dungeon, then died and turned dust along with Eodio's body.