Completed: January 27th 2019
The is a box with a figures market stall at Agora, Thebes. When you interact with him, he'll ask you to get him the last 5 Golden Herc Figures for his collection. Here's where they are.
Mission Start | Agora, Thebes
After you picked up the mission, go north to the fountain and through the passage at the back to get to the Alleyway as indicated on the map below.
Go north and enter the temple. The first golden Herc is at the back to the left (on the Map, marked with the "H"). Interact with it to pick it up.
Then leave the alleyway through the east passage (as indicated by the arrow).
The Big Olive
Cross the Big Olive to get to the Gardens as indicated on the map below
There are 2 Hercs in the Gardens. One is in a ditch and the other one in a small room at the top (indicated with the "H" on the map).
Then leave the area at the top as indicated by the arrow on the map.
There are 2 Hercs at the Overlook. Indicated with "H" on the map.
Go get the one at the very top first. It's where you entered Thebes the very first time.
The other Herc is high up on the big shield. You can only reach it when you come back from the top and jump off the roof onto the shield.
Take all 5 Hercs back to the boy to finish the mission.