The Night's Watch. Leal.
Event. Coste: 3.

Dominance Action: Choose a non-unique character with printed cost 6 or lower. Take control of that character. (Max 1 per round.)

"I pledge my life and honor to the Night's Watch, for this night and all the nights to come." from the Night's Watch vow
Eva Maria Toker
Core Set #139.

Link: Decklists

Take the Black

Rules FAQ

The timing charts on pg 25 of the RRG show that there is no opportunity for player actions until AFTER dominance is awarded.. So dominance is always counted before you would get a chance to use "Take the Black."

If you take control of a character with power tokens, those power tokens count towards your victory condition. RRG pg 16 "A player's power total is equal to the amount of power amassed on cards under his or her control".