Characters can also take Oaths which are fitting with the heroic age setting. Taking an Oath of Protection means you are sworn to come to another's aid in a time of need, much like the oath the kings of Greece swore to Menelaus which led to the Trojan war. Should you back down on your Oath you will suffer the curse of the treacherous which will cause the Eryines themselves to enact vengeance on you. Eryines are CR 12 creatures in the core 5e rules so it’s best not worth breaking an oath without a good plan or reason. This is a great mechanic for roleplay as it allows the player choice as to their oath and ties well into ancient Greek concepts like ‘Xenia’ (guest-friendship) that were seen as sacrosanct principles to uphold.
To start the adventure I used the detailed map of the city state of Estoria, ruled by the Dragonlord Pythor. The hook for the players would be to find Astoria, daughter of the king of Estoria who had recently gone missing after travelling to the glade of Thylea to worship. The culprit would be Nemea, a half-lion, demigod who also happens to be one of the sons of Pythor and a former tyrant who ruled the city of Estoria before Pythor. He is now back with a vengeance. His anger stemming from his abandonment as a child by his father Pythor, who did so because of a prophecy that a great kingdom would fall if he allowed his son to live.
I wanted a different take on the myth of the Nemean lion and to mix some other myths into the fray. There are some versions of the myth where the lion kidnaps folk in order to lure heroes into the lair to devour. I decided to go for this and make the ‘real’ target of the lion the player characters themselves. The Nemea was recruiting those to his cause who would aid him, such as his niece Astoria and perhaps the player characters themselves should they side with Nema and therefore the titans. This was to tie in to the tension I saw building between the titans and the mortals leading to a potential second war.