Good evening to all
sorry for my English is not very good
I would have some questions about the game:

1 replies on this forum are incontrovertible?
and apply in tournaments?

2 my enemy has a unit on the battlefield
a) declare the area to attack
b) its reporting units that attack
c) I declare the defenders
d) the damage is counted and assigns

I have in hand, seduced by the darkness,
I think I can play the card after step a), b) and c) to bribe the enemy units and prevent the damage, correct?

3 I play a mastiff war
I would like to activate its action
My opponent can play pilgrimage to stop me from doing 2 damage?

4 you can play the demonic sword on a corrupt unit?

5 I Grimgor as a development
play Rip Dere play? Eads Off! (above Grimgor "development")
the effect of forced Grimgor is activated?

or

I nogor raiders as a development
if development is destroyed
the effect of predators are active?

6 blu horrors when they die can bring into play pink horrors?

7 becouse warpstone mine is not limited?

very thank

1) The answers you will find here are usually given by experienced players, correct and based on the rules and the official FAQ. Sometimes you will see answers based on quotes by the developers, and it will say that the reply is from Nate, James, Lukas, or Caleb. Still, sometimes rulings change or get clarified, so nothing is 100% incontrovertible, but that doesn't mean answers you get here aren't correct at the time. If you require an official ruling, you can use the "Rules Questions" link at the bottom and contact the developers directly. I'd advise you to first check the FAQ at www.fantasyflightgames.com/ffg_content/warhammer_lcg/support/wh-faq-1.7%20printer%20friendly.pdf , the Rules Summary at deckbox.org/forum/viewtopic.php , and indeed search the forums here though, because your questions are comparatively basic, and you will easily find the answers to them and similar ones there.

2) This is the structure of the battlefield phase:

1. Beginning of the phase. Action Window.

2. Active player decides which of his opponent’s zones he is attacking, if any.

3. Action Window.

4. Active player simultaneously declares all attackers.

5. Action Window

6. Defending player simultaneously declares all defenders.

7. Action Window

8. Damage is counted then assigned, without yet being applied.

9. Action Window.

10. Damage is applied and its effects resolve.

11. Action Window.

You can use Seduced by Darkness (or any other action) during any Action Window. However, while corruption prevents a unit from being declared as attacker or defender, a unit that has already been declared will stay in the battle even if it gets corrupted. So if you want to stop a unit from attacking, you have to corrupt it in step 1 or 3 (or earlier in the turn). If you want to stop it from defending, you have to corrupt it in step 5 at the latest.

3) No. Once you have triggered the action of your Warhounds, it is on the chain, and will resolve even if he returns them to your hand. Once triggered, effects exist independently of their source.

4) Yes. The corruption of the unit isn't a cost or a requirement, just part of the effect.

5) No. The effect only triggers when the unit enters play, but the card was already in play as a development.

6) No. Just as it says on the card, Blue Horrors only allows you to "put another unit named Blue Horrors into play from your hand".

7) I'm not sure what the question is. Warpstone Excavation isn't limited, so you can play as many during your turn as you want. It is however on the restricted list, and you may only have one card from the restricted list in your deck.