How does Darius Legend work?

Darius, the Hand of Noxus Legend, functions as a resource-generating tool that allows you to gain extra energy during a turn.

According to the card text and the associated RiftJudge FAQ (FAQ #2457), here is how it works:

How to Activate

• Requirement: You must have already played another card (a Main Deck card) earlier in the same turn to satisfy the Legion condition.
• Action: You must exhaust the Legend to activate the ability.
• Timing: Because it has the Reaction keyword, you can activate this ability on both your turn and your opponent's turn (provided you have priority and have met the Legion requirement).

Key Mechanics & Nuances

• Immediate Resolution: As noted on the card and in the FAQ, abilities that add resources (like this one) resolve immediately and cannot be reacted to by your opponent.
• Chain Interaction: Using Darius mid-chain does not end the chain; other items already on the chain can still be reacted to after his ability resolves.
• Energy Usage: The 1 energy generated must be spent during the turn it is created, or it is lost. It does not carry over to the next turn.
• Not a Rune: Darius does not un-exhaust a rune; he functions as an additional source of energy for that turn.

Note: This information is based on the card "Hand of Noxus" (Darius) and the provided RiftJudge FAQ #2457.