Ok, it still seems as if the issue is unclear.
Here's the precise situation that had us confused:
Forcemaster has Initiative.
Forcemaster has a ready [mwcard=MW1J09]Temple of the Dawnbreaker[/mwcard] in play.
Beastmaster's Dire Wolf with face-down [mwcard=MWSTX2FFE02]Akiro's Favor[/mwcard] attacks Forcemaster and rolls 5 damage.
Questions:
1.) Who may/must decide first whether to reroll?
2.) If the answer to 1.) is Forcemaster due to having Initiative, can Dire Wolf reveal [mwcard=MWSTX2FFE02]Akiro's Favor[/mwcard] to reroll in response to Forcemasters decision?
3.) Would the answer to 2.) be different if Beastmaster had the Initiative?
4.) Would the answer to 1.) be different if [mwcard=MWSTX2FFE02]Akiro's Favor[/mwcard] were already revealed?
5.) Would the answer to 2.) be different if [mwcard=MWSTX2FFE02]Akiro's Favor[/mwcard] were already revealed?