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.
In order to play Fury of a Mob as a Naval action, do both Personalities have to be Naval or just one?
Fury of a Mob Battle: If your current army has more units than the current enemy army, bow your two performing Nonhumans and target an enemy unit: Destroy it.
In order to play Fury of a Mob as a Naval action, do both Personalities have to be Naval or just one?
Just one.
http://rules.l5r.com/CE_The_Player#Player_abilities: "In cases where multiple cards perform a Battle action, only one need be Naval."