As you can see from the image, priority is given after the active player (the turn player) has done all that he/she wants i.e.: has placed everything on the stack in the chosen order*. Then priority is passed to the opponent. If the opponent doesn't have anything to place on the stack as well or has finished stacking ablilities/summons, the next step will be resolution of the stack with a simple rule of thumb: "FIRST IN, LAST OUT".
Interchange between phases begin when the stack is empty and both players have neither anything to be placed further to the stack. During each phase, a new stack begins until it resolves. Bear in mind that a stack of abilities can never be created during the: Activate Phase, the: Draw Phase and the: End Phase. All stackable abilities and summons can only be done during the Main Phase 1, the: Attack Phase adn the: Main Phase 2.
Ok as we are more than competent with understanding the stack and its rules, let's take a look at abilities of characters you recruit to the field. During the Main Phases 1 and 2, recruiting a character doesn't use the stack unless that character has an Enter The Battlefield Effect (ETB). Let's take a look at some examples below:
The cards above both have an ETB effect. Take Al-Cid from Opus 2 for example. His ability requires you to CHOSE 1 ACTIVE Forward an opponent controls when he ETBs. Then you may play 1 Lightning Elemental Forward cost 3 or less from your hand onto the field. If this happens, you deal the CHOSEN Active forward 6000 points of damage. Now strictly speaking, one may decipher the ability as: the CHOSEN ACTIVE forward will only be dealt 6000 points of damage if I have played a Lightning Forward 3 cost of less from my hand on point of Al-Cid's ETB. This is not the case. Notice how the words CHOSEN and ACTIVE are capitalized? Well they are literally. Every ability has a cost. And in Al-Cid's ETB, the cost is to CHOOSE 1 ACTIVE forward an opponent controls. So say for example, you recruti Al-Cid, taking into account recruiting a character doesn't use the stack (an opponent cannot interact with abliities or summons when you recruit a character), but since Al-Cid has an ETB effect, this creates a window of opportunity for your opponent to interact with your play. So you recruit Al-Cid and you chose an active forward your opponent controls. In response to your Al-Cid ETB, your opponent reacts by using:
*Dull in basic terms is to tap*
Your opponent uses Edward's special ability by paying 2 Ice CP and dulling (tapping) Edward to dull his own forward. Have a look at the play by play below:
1. You recruit Al-Cid
2. You Chose Active Forward A controlled by your opponent
3. In response to your Al-Cid's ETB, your opponent uses Edwards sepcial ability and dulls his own Forward A.
4. Following the Steps of Frist in Last out; Edwards's ability resolves first followed by Al-Cid's ETB effect.
5. Now forward A is an illegal target mainly because Al-Cid has to target an ACTIVE forward.
6. Al-Cid's ETB effect fizzles. You will NEVER be able to play a Lightning Forward 3 cost or less from your hand after the stack is cleared
What we know from this? Al-Cid's ETB's cost is to CHOSE an ACTIVE Forward your opponent controls. If the cost cannot be fulfilled at this point of time, the entire effect of the abliity is fizzled. The same can be said if your opponent returns his Forward A to his hand in response to Al-Cid's ETB.
Often in a game you will be asked to refer to This Card A or This Card B. Lets look deeper into this with an example of Fleeting Flash:
Fleeting Flash states if you control another Manikin (character type) other than Fleeting Flash, Fleeting Flash gains +2000 power. So what happens if you control 2 Fleeting Flashes? They will buff each other with +2000 power. When a card refers to another card in its text, in this case a card with the same name, it ONLY refers to itself. Eventhough you can have multiple copies of Fleeting Flash in play (Maximum play set in a deck is 3), Fleeting Flash in its text refers to itself not other Fleeting Flashes in play under.
Well! Isn't that a mouthful? There are more FAQs and more stackable rulings to be reviewed. But lets keep what we learnt today as it is. Let us digest all these new information before we tackle the next chapter in one of the most awesome TCGS about to hit the top charts in the world! Come join us for FFTCG every Saturday at 2PM and mingle with the community! We have free demos every day we are open! Currently the set has expanded to Opus 3 (ETA June mid-late). We will be doing World Championships tournaments and many many more cool events for the most epic game genre in histroy: FINAL FANTASY!