You will find Testikles’ trainer, Alkon, training at the Demos in the south west of the city of Sparta. Speak with him to begin the quest. After navigating the dialogue options with Alkon, make your way south to the village of Gytheion to purchase some oil from Testikle’s favourite merchant. When you arrive at the village, use Ikaros to identify the precise location of the merchant and then go to speak with her. When she tells you that the oil is not available, choose ‘Can’t we work something out?’ and she will teach you how to make it yourself. When you approach the fire, choose the following:

• First, I light a fire.
• Oil of Athena.

The last stage varies for each player. Take note of the substance which the slave merchant mentioned and select the relevant dialogue option. When you are done making the oil, head west over the mountains to the Bay of Hades, where Testikles can be found. If you would rather avoid crossing over the mountains, fast travel to your ship and sail south and then west. The choice is entirely yours and only impacts which parts of the world you will explore first. When you arrive on the southernmost island of the Bay of Hades, loot the treasure at the Shipwreck of Nestor before you find and talk with Testikles. When he expresses aversion to sailing on the Adrestia, offer him the oil that you made to persuade him. With Testikles safely aboard the ship, you can now make your way to Elis, north west of the Bay of Hades.

When you arrive at Elis, dock the Adrestia and speak with Alkibiades. A series of dialogue options will ensue. It does not matter which you choose. At the end of the exchange, Testikles will fall into the sea and meet an abrupt end. You must now take his place in the Olympics. When you are done speaking with Alkibiades, the quest will complete.