Diana, Lunari

Q. I successfully conquer a battlefield with a unit that has Last Rites. Could I use Diana's legend ability to help me pay for the cost of reviving a unit?

A. I cannot. Since a showdown ends when both players pass Focus (348.), that means Diana can only spend that 1 energy during the Combat Showdown step (459.).

Since conquering happens during the Resolution Step (461.), we cannot use the [1] from Diana (even if it’s floating!)

Q: While controlling Diana Lunari and holding Ravenbloom Conservatory can you place Diana's trigger onto the chain, see the revealed Ravenbloom card and then choose not to pay Diana's Energy cost on resolution?

A: Once the moment to resolve her ability comes, you can choose not to pay Diana Lunari’s energy cost only if there’s no Energy “floating” in your Rune Pool.

The instruction to “Pay 1” does not read as “Add 1 energy to your Rune Pool and spend it”; it reads as “spend 1 energy in your Rune Pool”.

So if the player has Energy in their Rune Pool (as a “floating” resource), it must be spent during the resolution of the ability.

If the player has no Energy in their Rune Pool, they can put this resource in there (mid-resolution thanks to the Add rules) through the Add action, but they cannot be compelled to perform this action if they were not directly instructed to execute it; if they decide not to pay, the ability resolves to no effect.

Not relevant to the question, but still relevant for a deeper dive:

Three important final reminders about Diana Lunari’s triggered ability: (1) Due to its formatting, “paying 1” is not considered as paying a cost. (2) The “you may” part after the condition specifically refers to the choice of putting the ability on the chain when the trigger condition is met. (3) The ability goes pending on the chain before attack and defend triggers in the same combat chain.

Relevant rules:

• From the Unleashed FAQ: “[...] now there is even more differentiation, as “if you do” templating isn’t a cost within instructions and therefore cannot be the base cost of the triggered ability. Even if resources are instructed to be spent, as in the case of Draven, Vanquisher (RIP), who reads “When I attack or defend, you may pay [C]. If you do, …” those resources are not a cost and are paid on resolution of the ability and not finalization”.
• From the Unleashed FAQ: “A “you may” that appears next to the conditional: “You may,” - this indicates the decision of whether or not to place the ability on the chain”.
• 429.3. Activated abilities that Add resources and have the Reaction tag can be activated during the playing or resolution of other spells and abilities, any time that those spells or abilities require resources be paid.

Q. Do I pay 1 on finalization or during resolution?

A. On resolution. The template When… you may…. If you do make the requirement be executed at resolution (same as with Jayce and Draven).

Q: My enemy moves a <<Kha’zix Evolving Hunter>> to attack my <<Diana Lunari>>. A <<Tactical Retreat>> is at the top of my deck. Is it possible to draw and play the <<Tactical Retreat>> before Kha'Zix's ability can kill my Diana?

Rules for Context - FAQ “How does HOT FEPR actually work?”, 322.1., 459.2.

A: No.

Diana’s triggered ability goes on the same chain as Kha’Zix’s attack trigger, but it triggers before any triggered abilities that occur as a result of units gaining the attacker or defender designation.