Simorgh
The bird that raised Zal. The feather is hers.
The Simorgh nests on Alborz and is older than the story she shows up in. She is not a monster to kill and not a god to pray to. She is closer to a doctor who happens to be the size of a house. She found the infant Zal left out on her mountain and raised him.
When she gave him back, she left him one of her feathers and a rule: burn it and she comes. The rule is the good part. Help exists, it is real, and it is neither free nor endless. You are carrying the one thing you are allowed to spend, and every time you look at it you have to decide whether this is the moment.
It gets burned twice in the poem. Both times what she brings is knowledge rather than muscle. She explains how the thing is done, and then leaves them to do it.
In the game
The feather is in the game, and it behaves the way the poem says: you have one, burning it is a decision, and it is not the sort of help that turns up twice on its own.