"(except the Ring-bearer)", as otherwise, this could be instant corruption.

I’m not so sure, because firstly you have to have a wounded Wraith and make them strength -2, and it’s the Free Peoples player’s choice who to assign. Convince me and I’ll happily change it.

• Terrors of Dol Guldur
Condition • Support
At the start of each skirmish involving a minion and a companion with resistance 3 or less, you may exert that minion.
Response: If a twilight minion wins a skirmish, discard this condition to add a burden.
H3 C 174

• Call of the Rings
Condition • Support Area
While the Ring-bearer wears The One Ring, each twilight minion is strength +1 and fierce.
Skirmish: Heal an enduring Nazgul to discard a ring artifact borne by a companion they are skirmishing. Discard this condition.
H3 R 155

• City of Evil
Condition • Support Area
At the start of the maneuver phase, the Free Peoples player may add a burden to Unlock this condition until the regroup phase.
Each Nazgul gains toil 1.
Locked: Each minion is vitality -1.
H3 R 144

There are several ways to assign Nazgul (and other minions) to a specific companion, including the Ring-bearer...Return To Its Master, for example. It’s not much, but there ARE ways, and they would lead to very powerful (if not all-out broken) combos. It’s just safer to exclude the RB, I think.

YIKES! The old twilight Nazzies just got a BIG boost! Maybe too big...see what other reviewers say. I think you can drop "artifact", since I don’t know of any non-artifact rings.

I’m not sure I completely get it. Why would the FP player EVER want to unlock this? Wouldn’t they want to lock it instead?

• Terrors of Dol Guldur
Condition • Support
At the start of each skirmish involving a minion and a companion with resistance 3 or less, you may exert that minion.
Response: If a twilight minion wins a skirmish, discard this condition to add a burden.
H3 C 174

You missed the word area off. Awesome condition may need cost 3 though and id lower it to res 2.

• Call of the Rings
Condition • Support Area
While the Ring-bearer wears The One Ring, each twilight minion is strength +1 and fierce.
Skirmish: Heal an enduring Nazgul to discard a ring artifact borne by a companion they are skirmishing. Discard this condition.
H3 R 155

Sweeeeet. Although "and fierce" is nasty, id consider changing that to something else less evil.

• City of Evil
Condition • Support Area
At the start of the maneuver phase, the Free Peoples player may add a burden to Unlock this condition until the regroup phase.
Each Nazgul gains toil 1.
Locked: Each minion is vitality -1.
H3 R 144

Perculiar but acceptable in terms of mechanism. Unfortunately i think its too nasty either the locked part needs to be harsher or the toil bit needs to be strength +1 or something similar. Toil is awesome even if they werent enduring.

Thranduil

• Terrors of Dol Guldur
Condition • Support
At the start of each skirmish involving a minion and a companion with resistance 3 or less, you may exert that minion.
Response: If a twilight minion wins a skirmish, discard this condition to add a burden.
H3 C 174
maybe each time it is assigned to a skirmish.

• Call of the Rings
Condition • Support Area
While the Ring-bearer wears The One Ring, each twilight minion is strength +1 and fierce.
Skirmish: Heal an enduring Nazgul to discard a ring artifact borne by a companion they are skirmishing. Discard this condition.
H3 R 155
while, first of all NO DISCARDING ARTIFACTS!!!!! second of all, I see why this is necessary. limit it to dwarven rings and I will let you live. it makes more sense story wise that way annyways.

• City of Evil
Condition • Support Area
At the start of the maneuver phase, the Free Peoples player may add a burden to Unlock this condition until the regroup phase.
Each Nazgul gains toil 1.
Locked: Each minion is vitality -1.
H3 R 144

• Ring of Twilight
Artifact • Ring
Vit: +1
Bearer must be a Nazgul.
Bearer gains terror 1 and twilight.
Regroup: If a player reconciles, return bearer to your hand.
H3 R 162

There must be a better name than this. Ring of Shadow, Ring of Torment, Ring of Pain...

And while we’re on a very similar subject:

Winged Beast
Possession • Mount
Str: +2
Vit: +1
Bearer must be a Nazgul.
Bearer gains winged and terror 1.
A creature of an older world, maybe it was, whose kind, lingering in forgotten mountains cold beneath the Moon, outstayed their day, and in hideous eyrie bred this last untimely brood, apt to evil.
H3 U 185

This seems very powerful, especially for Dol Guldur. remember that the Wraith’s flying mounts weren’t revealed until the War of the Ring. A black steed might be a more appropriate mount for this set, though I see that it would lose the winged keyword.

Thranduil

There must be a better name than this. Ring of Shadow, Ring of Torment, Ring of Pain...

This seems very powerful, especially for Dol Guldur. remember that the Wraith’s flying mounts weren’t revealed until the War of the Ring. A black steed might be a more appropriate mount for this set, though I see that it would lose the winged keyword.

• Ring of Despair
Artifact • Ring
Str: +1
Bearer must be a Nazgul.
Bearer gains fierce and twilight.
Regroup: If a player reconciles, return bearer to your hand.
H3 C 161

• Ring of Shadow
Artifact • Ring
Vit: +1
Bearer must be a Nazgul.
Bearer gains terror 1 and twilight.
Regroup: If a player reconciles, return bearer to your hand.
H3 R 162

Shouldn’t both of those be response actions, not regroup?

Shouldn’t both of those be response actions, not regroup?