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, 26 September 2009
It is understood that in order for an action to be successful one of it's effects has to produce one or more actual changes in game state, but would an action that has the single effect of destroying a personality be successful if the destruction is prevented with Duty? Just double checking, but I believe the answer should be no. Even though the state of the game is changed by the destruction of the personality performing Duty his destruction is brought about by Duty's reaction, not the orginal action which is being prevented.
Duty Reaction: Before another player’s card’s effect destroys one of your Personalities, destroy your target honorable Samurai Personality at the same location: Negate the first Personality’s destruction.
Thanks for your time.
A player, 26 September 2009
would an action that has the single effect of destroying a personality be successful if the destruction is prevented with Duty?
No. If all effects of an action are negated or otherwise fail to occur, the action is not successful, and Duty negated the action's single effect of destruction.
Glossary, Successful: "Effects that are negated, that do not occur, or that had a one-time effect but failed to affect anything, are not actual changes in the game state."