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.
Hello,
If I begin an attack phase, and I assign Hida Kuon to province A, while my opponent assigns a defender to province B. If I resolve Kuon's battle, take the province and then march beyond death him to province C and take that province, when resolving province B battle, would I be able to Will him into that battle as well?
Hello,
If I begin an attack phase, and I assign Hida Kuon to province A, while my opponent assigns a defender to province B. If I resolve Kuon's battle, take the province and then march beyond death him to province C and take that province, when resolving province B battle, would I be able to Will him into that battle as well?
Yes.
The rule only prohibits movement of someone who has been in battle resolution as the Attacker to another battlefield in the same phase.
You may indeed use Will in the manner you specified, assuming you also have presence at Province B.