I have Emissary of Grudges in my deck and I was wondering if I use it correctly. In exemple:
I play Emissary of Grudges and I secretly choose player 2.
Player 2's turn. He casts Clone and targets me with its ability:
You may have Clone enter the battlefield as a copy of any creature on the battlefield.
First question: Can I use Emissary of Grudges's ability as an instant?
If so, can I "cancel" Clone's ability, and use it myself on anyone?
In example, could I choose to target Player 3? Or am I forced to use it on its owner?
Last question: if Emissary of Grudges leaves the battlefield, do I keep this ability? Or do I just throw out the chosen player's name?