Situation:

-Melee game.

-Player A Baratneon has Fury of the Stag plot and is Active player.

-Player B Martell controls Arianne Martell (PotS) with Thirst for Blood attachment and 4 Power on her.

-Player A wins a Power challenge against Player B, and chooses Arianne Martell to take control of her.

-Next round Player B Martell plays Arianne Martell since he doesn't control her anymore.

-On the same round, Player C Stark wins a challenge in which Roose Bolton (DB) participated, and triggers his effect: "Response: After you win a challenge in which Roose Bolton participated, all players take control of each character they own currently in play."

What happens with Arianne Martell which controls Player A Baratheon?

Does she returns to Player B as a duplicate on current Arianne Martell he controls at that very moment?

Does she returns as main Arienne Martell and current Player's B Arianne Martell becomes a duplicate?

What happens with Power on returned Arianne Martell and Attachments on her?

I found this very interesting situation, and probably not so common situation as well.

Thanks in advance.

Situation:

-Melee game.

-Player A Baratneon has Fury of the Stag plot and is Active player.

-Player B Martell controls Arianne Martell (PotS) with Thirst for Blood attachment and 4 Power on her.

-Player A wins a Power challenge against Player B, and chooses Arianne Martell to take control of her.

-Next round Player B Martell plays Arianne Martell since he doesn't control her anymore.

-On the same round, Player C Stark wins a challenge in which Roose Bolton (DB) participated, and triggers his effect: "Response: After you win a challenge in which Roose Bolton participated, all players take control of each character they own currently in play."

Your whole situation is moot because of the highlighted statement.

As a unique card, Player B CANNOT play a second copy of Arianne Matell. The rules for unique stop you from playing or taking control of a second copy of a unique card if you own or control a copy that is already in play, or there is a copy in your dead pile.

Player B owns the copy controlled by Player A, so the rules do not allow him to play a second copy of Arianne while that first copy remains in play (no matter who controls it).

If I took control of an unique character, and also have my own copy of that character (in my hand, not in play), would I be able to use my copy to duplicate the one that I have taken control off?

"FAQ (3.29) Unique Cards and Changing Control

You may not play, put into play, or take control of a unique card already in play that you own or control (except for putting a duplicate on a card that you own and control), or that is in your dead pile.

Thus you cannot take control of a unique character that you already have in play. You cannot play a unique card if your opponent has taken control of another copy of that unique card that you own.

Duplicates can only be played or put into play on cards you own and control."