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, 23 June 2011
Had a discussion with a friend regarding The God-Beast Unleashed:
Choose one of your Personalities in play. Discard the top card of your fate deck. Give the personality a bonus to his Force, Chi, or Personal Honor equal to the discarded card's Focus Value.
Without an explicit constraints block in the text we faced a little confusion about whether or not the rest of the event still resolved if there were no personalities in play to target.
Would the player still discard the top card of his deck?
Would the event not resolve at all?
If not, can a reaction shuffle it back into the 'before it resolves'?
Zen Faulkes (rules official), 23 June 2011
The God-Beast Unleashed: Without an explicit constraints block in the text we faced a little confusion about whether or not the rest of the event still resolved if there were no personalities in play to target.
It doesn't target. http://rules.l5r.com/CE_Glossary_T#Targeting: "just “choosing” something is not targeting."
So away goes that top Fate card.