LilyDraken
The Lily of Westeros
From what we have seen they have all blue eyes. Except the Undead Mountain. I'm not sure what colour his eyes are at the moment. I still strongly believe he can do nothing if the Night King would confront him. To me the Night King is a necromancer and he would have power over the Undead Mountain - to control him as he wish. Cercei and all her men could not stop it. Or him after that happens.
That's something I didn't even think of! But yes, it's possible the Night King could have power over the Mountain. What an interesting theory!