I have a Paladin with Fighting Style: Protection. Both I and the DM are unclear on when the reaction to impose disadvantage on an attack roll can be used: Do you have to react prior to the first attack roll, or can you react after seeing the result of the first roll?
"When a creature you can see attacks a target other than you that is within 5 feet of you, you can use your reaction to impose disadvantage on the attack roll. You must be wielding a shield."
First, it will only apply to one attack roll, regardless of how many attacks the creature gets against the target. Second, as soon as the creature declared an attack is when you should use this. In normal play, the DM is going to roll and give you the attack score really quick and not sit and wait for someone to decide if the d20 rolled is high enough to warrant giving disadvantage.
Undrhil got it.
If the enemy has multiple attacks, you can choose which attack to use your reaction. For instance, a ghoul might first bite, then claw. You'll want to protect against the claw because it paralyzes. Whichever attack you choose to react to, you declare it before the enemy attack roll.
There's a decent homebrew feat and discussion for Protection here, and more ideas for bringing Protection up to par with other fighting styles without buying a feat here
We always roll 2 d20 and designate one as the primary d20. Then, if it turns out that you had advantage or disadvantage, its already been rolled. There isn't really a rule on this, but it would slow down gameplay to make your decision about imposing disadvantage on the basis of having seen the first d20, and that would make it a super dissociated mechanic--I mean, is your paladin waiting to see if the blow lands before deciding whether to thrust his shield in front of the sword? In any event, the trigger of the reaction is 'attacks,' not 'hits'...
Hreth wrote:
Thanks for all the answers. I'm probably going to use the Tier 1 character rebuilding rule in the Adventurers League Player's Guide to recreate my character with Fighting Style: Defense instead.
There is nothing wrong with FS: Protection *at low levels*. However, at higher levels, the disadvantage might not be enough to matter. And, of course, there are those DMs whose luck with the dice seems to make disadvantage not matter at any level. (Those DMs need to go to Vegas...)
Undrhil wrote:
mellored wrote:
Nevvur wrote:
A once/round imposing of disad is gold, imo, esp at low levels, but I expect also very useful at higher levels. And all you need to do is stand next to the guy you're protecting, the attacker can be anywhere, but you can still defend the guy beside you.
Plus, shield mastery feat. Thats some badass warrior right there.
Psikerlord wrote:
FrogReaver wrote:
Psikerlord wrote:
Psikerlord wrote:
Ahh.... but protection style and sentinel are not mutually exclusive, and both are good in different scenarios. For the record I think sentinel is also gold (esp for a ranger fighting with a pet).
And although you only have one reaction, having more options is better than having less.... And as a fighter, you have lots of feats to around...
In my group, the fighter has the protection style, and the rouge has the Sentinel feat. If you attack the rogue, you get disadvantage. If you attack the fighter, you get stabbed in the ear. If you attack someone else, you get all of the above. It's really unfair. 
Slaunyeh wrote:
Slaunyeh wrote:
Strill wrote:
Strill wrote:
Slaunyeh wrote:
Strill wrote:
The only use of protection is that you might get to save the wizard from dropping during a few combats. It's a pretty shining and memorable moment... but that doesn't make it mechanically good.
Slaunyeh wrote:
Also of note, protection does not break invisibility. Where as sential would.
Nevvur wrote:
Strill wrote: