Suppose another player's action destroys Gate Guardsman or the personality it's attached to. I react with Fortified Camp to save it. Can Gate Guardsman still use it's own reaction as triggered by the action that destroyed it.
Gate Guardsman & Fortified Camp
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.
Reaction: After another player’s action destroys one of your attachment cards or it’s Personality: Attach the card to one of your target Personalities (paying all costs).
Reaction: After another player resolves a Battle Action, if this unit is at the current battlefield: Take an additional Battle action.
So Fortified Camp gets used in the middle of the offending Action's "Resolve Effects" step. It brings back the Gate Guardsman.
Gate Guardsman gets used after the offending Action's "Resolve Effects" step is over. It is returned to play in time to use its Reaction to the very Action that first killed it.