A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
A player, 9 July 2012
Suitengu's Torch says: Reaction: After you announce a Thunder Battle action: Its effects will not be negated or delayed.
Inexorable says: Reaction: After another player announces a Reaction during the Combat Segment: Its effects will not negate other effects.
If I attack a Mantis player and he, as the defender, plays the first action as a Thunder action send home with the Reaction off the stronghold, can I use Inexorable to counter the effects of the stronghold reaction and then play a movement negation card?
Alex Jones (rules official), 10 July 2012
Suitengu's Torch says: Reaction: After you announce a Thunder Battle action: Its effects will not be negated or delayed.
Inexorable says: Reaction: After another player announces a Reaction during the Combat Segment: Its effects will not negate other effects.
If I attack a Mantis player and he, as the defender, plays the first action as a Thunder action send home with the Reaction off the stronghold, can I use Inexorable to counter the effects of the stronghold reaction and then play a movement negation card?
No.
A negation effect can itself be negated or otherwise prevented, but "will not" is not preventable.
See Effects, "Does not/Will not" versus Negation: These phrasings are equivalent in the way their form of prevention works, and the rules on prevention below refer to both of them. The main difference between the two is that in the card set, negation effects are sometimes specifically prevented with wording such as "will not be negated," whereas there is no such wording to prevent "does not" effects as a specific category.