This may have been covered before, but on abilities like Improved Iron Will can you reroll a natural 1 since you automatically know the result regardless of the DC? Can you force a re-roll on an opponents natural 20?
I would say yes.
I believe you can, as the one who reveals the result is the DM, just because I (the gamer) knows a 2 fails (with a wisdom score of 7, 1st level fighter) doesn't mean I (the PC) can't use this ability before the DM reveals the result. "Once per day, you may reroll a will save. You must decide to use this ability before the results are revealed. you must take the second roll, even if it is worse." Yes, I realize that a 1 always fails... so it is kind of vague, however the DM always determines/reveals the result, so as long as you beat the DM to the reroll before he reveals, good to go imo.
As for an opponent... I don't see any reference to opponents will saves anywhere, so no... unless I am missing something...
This may have been covered before, but on abilities like Improved Iron Will can you reroll a natural 1 since you automatically know the result regardless of the DC? Can you force a re-roll on an opponents natural 20?
If you, through trial and error, discover what the save DC against a gaze attack is, are you then forever barred from using Iron Will against that gaze because you know as soon as you roll if you passed or not?
"Before the results are revealed" means "before the results are revealed ~by the DM~".
Now I can see a ruling about natural 1s and 20s not being affected by reroll powers because they are critical successes/failures and outside the realm of luck to influence, but RAW you can use a reroll on them.
Abilities like this are metagaming abilities. You are using knowledge about something that your character has no idea. How do they know they rolled an auto fail and then decide to rewind history?
In for a penny, in for a pound, when dealing with these abilities IMHO use all the meta knoweldge you like including rules of 1s and 20s to make your call. I also agree that the DM is the one that ultimatly does the reveiling. they could for instance say "yep, the 20 fails because X".
I also agree that the DM is the one that ultimatly does the revealing. they could for instance say "yep, the 20 fails because X".
Agreed.