If the valley is his source of power, it also means his enemies can sneak someone in there to dispel the miasma and weaken him. My guess is that he will revive his hero lover, and she will sacrifice herself to purify the valley, making it a full cycle.
Army insta teleport is OP. Even if the enemy has strong troops/heroes, you can teleport your army into towns/cities, effectively holding their populace hostage.
Whats the point of giving waifu to a skeleton. It will only ruin the story...
Tho ofc it would be fun if she's the treacherous type constantly looking for opportunity to backstab