Once you place the Staff of Hermes at the Shrieking Ruins, you will be left with a riddle.
To solve this riddle all you have to do is bring a turtle all way to the firepit in the Shrieking Ruins.

You can find a turtle really close southwest from the entrace of the ruins. It is also marked by an interactive item called "Turtle Eggs".



If you do not see a turtle there, you must have already killed it.
To get a new one, respawn all enemies or reload the game.

Once you see the turtle, do not kill it but kite it all the way to the ruins. Do not kill it until you see a shimmering yellow light around the firepit. That signals to you that the turtle is close enough and you can kill it now.

After killing it, the firepit will light up and you will get your reward.

Congratulations, you've made Hermes happy.