When a player possesses an opponent's unit with Deathknell and that unit dies, which player gets the Deathknell effect?

Ruling: The controller of the unit (the player who possessed it) gets the Deathknell effect, while the card goes to the owner's trash.

Nuances:

• This ruling is based on developer intent (red text) rather than the current rulebook text
• The rules will be updated in version 1.2 to reflect this clarification