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.
Is Daigotsu's ability permanent? If I can prevent the destruction of the personality is his control permanent?
Which wins out kuon's text that says negate the first action targeting him or Knife in the Darkness which says the movement cannot be negated?
[Mod edit: Thread title. Please make them descriptive. Also, please use complete card titles and Experience levels. There are a lot of cards out there with "Daigotsu" and "Kuon" in the title. Thanks! -ZF]
Is Daigotsu's ability permanent? If I can prevent the destruction of the personality is his control permanent?
Change of control is not "permanent" in the game sense of being an effect with a duration that last until the end of the game. Rather, it is an instantaneous effect with no duration; like dishonor, it happens and that's that. Unlike "permanent" effects which could later have their duration ended by negation, there is no un-doing it, except by a further effect.
So, that's a long way around to "yes", but yes. If you can prevent the destruction somehow, there is nothing default or implicit that would return control of the stolen Personality to his original controller.
Which wins out kuon's text that says negate the first action targeting him or Knife in the Darkness which says the movement cannot be negated?
Kuon doesn't say "negate", he says the effects "do not" happen. Knife only prevents "negation", explicitly, so Koun's trait would stop the effects of Knife.