B · Engine & Sequencing · §7
What counts as playing a card from outside your hand, what does not, and why the answer to that question decides three card evaluations.
When you play a card from anywhere other than your hand, empower . As an Action, you may disempower and exhaust the Legend to give a unit Assault 2 for the turn, which is +2 Might while it is an attacker.◆src
Tokens. The core rules state plainly that tokens are not cards, and that a token is played by following the steps for playing a card rather than by being one.◆src
is still an engine card, but only on its second use: the Flow replay from the trash is a card played from outside your hand, and the tokens it makes either time are not.
and both carry Hidden, where you set the card aside for an Action cost and play it later for zero. Whether that later play counts as playing a card from outside your hand depends on which zone a hidden card occupies, and the rules text available at the time of writing does not resolve it.
burns two on entry, which stocks the trash, and on conquer it gives a spell in your trash Flow equal to its cost for the turn, which spends it. One card starts the engine and feeds it, and playing it from the Champion Zone empowers the Legend before either trigger resolves.
Empowers accumulate. There is no cap in the text and no reason to stop generating them except opportunity cost. What is capped is the conversion: one disempower per exhaust, one exhaust per turn.
A Legend is not a unit and does not sit on a battlefield, so the usual removal in this format does not reach it. The realistic failure is not losing the Legend; it is generating empowers in a game that ends before you have turns to spend them.