Timing Question

[Milevan_Faent]

What is the timing for Defenses and Mandatory Enchants? For example: Block, Forcemaster, and Forcefield. If I have Block on my Forcemaster, and his Defense goes off successfully, do I still need to reveal Block? Likewise, if I have a Forcefield up, since it says it happens before Avoid Attack, does that mean I don't have to use Block?

[Puddnhead]

Forcefield cancels the attack before the avoid attack step and you would not be able to reveal a defense.

Both Block and Deflect are defenses. You cannot use both on the same attack. If the attack reaches the "Avoid Attack step",  Block must be revealed. In this case it is always superior to use the revealed block over the optional Deflect (unless you have only 1 mana)

[Milevan_Faent]

And what happens if you don't have enough mana to pay for the mandatory reveal?

[Puddnhead]

And what happens if you don't have enough mana to pay for the mandatory reveal?

The spell must be revealed because the trigger occured, but you do not get its effect.  So, make sure you have the mana

[Zuberi]

With any enchantment, you always have to option of revealing it without paying for it. If you do so, the spell fizzles and is discarded without effect. With spells like Block, revealing it is mandatory but paying for it is not. So, when you reveal, you have the option of paying to get it's effect or letting it fizzle. If you don't have the mana to pay for it, you have to let it fizzle. Also, if you've already used a Defense on this attack, you can not use another Defense, so you wouldn't be able to get the effect of Block even if you paid for it.

(Note the limitation is one Defense per attack, not per attack action)

[Coshade]

A banana sticker for puddn today. Nicely done
Also Zuberi's explanation is spot on