if personality A assigns to Battle D and later dies, and I bring him back somehow but he is now at my home, can "back to the front" be used to send him back to battle D?
dead personality and back to the front
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.
if personality A assigns to Battle D and later dies, and I bring him back somehow but he is now at my home, can "back to the front" be used to send him back to battle D?
Yes, you may. As long as the Personality didn't go facedown and out of play, he remembers where he assigned and Back to the Front may be used to send him back there.