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.
Essence of Gaki-do reads: Bow this Shugenja, even if he is home: you may targer and bow any of your other Shugenja at any location: Create a number of 2F/2C Spirit Personalities at the current battlefield equal to the number of Shugenja bowed. After the battle ends, remove these Personalities from the game.
Since this is an action that creates presence, will you need presence in the current battlefield to perform it?
Same question can be applied to Yobanjin Fortress.
Essence of Gaki-do: Since this is an action that creates presence, will you need presence in the current battlefield to perform it?
As noted under Rules Changes, creating a unit where you have no units is not legal.