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.
Open: Pay Gold equal to the total Gold Cost of the targeted Personality's unit: Lose 3 Honor. Take control of a target Personality. While you control him, you may not assign his unit to attack and he will not move to attack. Before this turn ends, give control of him to his owner.
What happens when you use enticement on a unique personality that you already have in play?
Illegal target, dies because they can't exist together on your board, or successfully enticed?
Open: Pay Gold equal to the total Gold Cost of the targeted Personality's unit: Lose 3 Honor. Take control of a target Personality. While you control him, you may not assign his unit to attack and he will not move to attack. Before this turn ends, give control of him to his owner.
What happens when you use enticement on a unique personality that you already have in play?
Illegal target, dies because they can't exist together on your board, or successfully enticed?
Glossary, Unique: If the Unique card is in a unit that would change control to a player who already controls a Unique card with that title, the entire unit fails to change control.