(This represents 1 of your Stamina. 4 copies of this start on the field on your side.)

A Marker.
Notes:
- Stamina is a kind of game piece called a marker. Markers can't be added to a deck.
- Markers that leave the field — for example, by being discarded — are moved beside the game, in reserve, rather than mix with your other discards; markers also go to reserve if they would go to your deck or hand.
- You have a value called Stamina, which matches how many of your Stamina markers are on the field. Each represents 1 of it.
- To lose Stamina, discard that many of your Stamina markers. To do so to pay a cost, you must have at least that many to discard, or you can't pay it.
- You don't need to use a specific card to represent a marker, but this reminder card looks nice if you want to use it. You can track markers with any method you want (for example, with a single reminder card and counters), as long as it's clear whose, where, and how many there are.
- Future markers may have specific game text with other effects, but Stamina markers do not.