Unchained Monk -- Furious Defense Timing?

[Balkoth]

Furious Defense allows you to use an immediate action to gain 4 AC. Say an enemy starts next to you and then full attacks you. When exactly can you use this?

A, at the start of an enemy's turn
B, after the enemy attacks you but before the d20 is rolled
C, after the d20 is rolled but before damage
D, something else?

[Nina Luna]

You should be able to use immediate action anytime even if it´s not your turn, so I guess you can use it as soon as an attack against you is declared?

[Fuzzy-Wuzzy]

You could declare it at the start of your enemy's turn, but you'd usually do so when they target you. Once the d20 is rolled you are "inside" the enemy's action, and you can't take even an immediate action then. (Also you'd be looking for a retroactive effect then, and those are always called out.)

[Trekkie90909]

You can use an immediate action at any time; note however that as soon as the results of the d20 roll have been revealed the attack has already resolved either as a hit or miss, so it is most advantageous to use it for B. You can use it in any of the above scenarios, in A they might not target you, and in C the attack may have already hit, but it'd apply against later attacks; D is also viable, but again might be situationally less useful.

[Balkoth]

Fuzzy-Wuzzy wrote:

You could declare it at the start of your enemy's turn, but you'd usually do so when they target you.

Is there a difference between them "targeting" you and them rolling the d20 to attack you?

[Fuzzy-Wuzzy]

Balkoth wrote:

Fuzzy-Wuzzy wrote:

You could declare it at the start of your enemy's turn, but you'd usually do so when they target you.

Is there a difference between them "targeting" you and them rolling the d20 to attack you?

Yes, targeting (decision to attack you) is what leads them to roll the die. Once they roll the die and the GM declares hit or miss, it's too late to usefully raise your AC (even if you can take an immediate action then); the ability is not retroactive. I suppose you could do it between the GM rolling the die and the GM declaring hit or miss, but what's the point of that over doing it between the targeting and the roll?

[Balkoth]

Fuzzy-Wuzzy wrote:

Yes, targeting (decision to attack you) is what leads them to roll the die.

If targeting is separate from attacking, does that mean the attacker can change targets if he sees the monk use Furious Defense and he hasn't actually attacked yet?

[Fuzzy-Wuzzy]

Balkoth wrote:

Fuzzy-Wuzzy wrote:

Yes, targeting (decision to attack you) is what leads them to roll the die.

If targeting is separate from attacking, does that mean the attacker can change targets if he sees the monk use Furious Defense and he hasn't actually attacked yet?

Why would it mean that? When you've decided who to attack, you've decided. Don't overthink things.