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.
It states that "Unstoppable effects cannot be prevented." Furthermore, the rule book says that you can't use interrupts on unstoppable actions.
Does this mean the Scorpion Stronghold -can- be used to name cards and negate their effects the first time they are used later in the turn?
Does Shield Wall's trait count as "prevention" and thus it's ignored?
It states that "Unstoppable effects cannot be prevented." Furthermore, the rule book says that you can't use interrupts on unstoppable actions.
Does this mean the Scorpion Stronghold -can- be used to name cards and negate their effects the first time they are used later in the turn?
Does Shield Wall's trait count as "prevention" and thus it's ignored?
"Unstoppable", by the Rulebook, means such an action can't be Interrupted by other players. What the Stronghold trait does is give your Unstoppable actions ADDITIONAL immunity to prevention (which includes negation). So, that's two separate things.
But negation is prevention, so the Scorpion Stronghold can't affect the Knot player's Unstoppables.
However, Shield Wall restricts a player's ability to target a unit. While this IS prevention, it is prevention of targeting. Targeting is not an "effect", and the Knot only stops Unstoppable actions' "effects" from being prevented. So, nothing about Unstoppable or the Stronghold would allow a Knot player to target a Shield Wall's units' cards with Ranged Attacks.
I hope that clarifies.