The obsidian treasures

[Phantomfrettchen]

So i've always liked the idea of this set. But in practice it's never used.
Sure some of the items are actually good to use, but weirdly enough, people rarely if ever use them together. By the time you have acquired 40 shadow power(the most you can realistically get in a single run without vault and even this is up to chance) you are usually much better off using other equipment anyway, resulting in the use of only some of the items. This is mostly due to the set bonus not being good enough to compensate for the lack of strength of singular lower tier items from it.
In addition to this the item set is geared towards hybrid characters, using both spellcasting(black ring and black core). With black ring being exclusively useful for spellcasters, resulting in a cost for equipping it for every non-spellcaster.
In addition to this the set itself grants rather specific resistances. With most resistances coming from the Black Plate and resistances being limited to 5 elements from 7 item slots and only 3 of them high. Even the black wall cannot really make up for this, as 0.4*shadow power results even with heavy investment only in 40 shadow power and therefore 16% all res.
In fact, even immunities come short as well, as between boots, necklace, helmet and rings occupied, one cannot really get stun immunity or silence immunity at all. Confusion, Blindness and Fear immunity are nice, but not sufficient for a lategame item.
Nothing to be too crazy about, especially given that if one goes for the 2h, one doesn't even get this bonus. In addition, necessary immunities are only provided by the black plate.
The set only attempts to make up for the lack of powers it does not provide, with 40 spellpower and phys power being provided. Certainly not bad, but nothing to write home about either.

Now there are two options of how one were to buff this set:
Make everything decent in the slot they are.
this would be a curious change, as most of the items are actually pretty decent(except maybe shield and the boots) on their own for their tier. To alleviate it in this fashion would require the game to tier up almost all items from the set. Something which would be a little weird in the first place.
That being said, this could be interesting to alleviate some of the resistance and immunity problems by buffing the black wall, maybe the black ring or the black boots with some resistance/immunity.

Improving the set bonus.
This is much better, as it alleviates the problem without actually needing to make the entire set high tier.
With the set bonus, each item needs to be put up to the value of a (semi-) high tier item. As you are not going to be able to wear the whole set till lategame anyway.
I will now go over each item and it's bonuses.

The black plate
Really good item. The set bonus only improves an already top tier lategame item. Not much of a change needed.
The Black Crown
Not a bad item with decent, if not amazing defensive properties. The set bonus gives some saves, which are nice. Could maybe put an immunity here, but not strictly needed.
The Black Core
At it's tier, this is an amazing item. An effective hundred life, immunity to blindness, infravision and darkness resistance are pretty good. The Shadow Power bonus only sort of makes up for not being able to wield any other items boosting spellpower.
The Black boots.
These are bad. Even at their item tier, they are never used and even if they provide a 100% movement speed bonus with the set, this does not really alleviate the lack of a boots slot, as they provide no other bonuses. These definitely need a boost, and probably both on the base item and the set bonus. This would be a decent place to put some resistances and some immunities. Resistances would probably best fit on the base item, while the set bonus would have to be augmented with immunities. For example this could be 1-2% stunning or/and pinning immunity for each shadow power. This may sound overkill, but the item is just that bad.
The Black Ring
This one is a weird one. This item is pretty much caster exclusive, as for everyone else it provides just a low bonus to darkness and fire damage. For casters, this is a pretty good item with it's on spell-hit cast effect and spellcrit chance. Too bad that the set is geared towards hybrid characters, as these usually prefer hitting an enemy over casting a spell, therefore making this item nigh-useless for most characters that want to use it. In addition to this, this in a ring-slot which usually grant resistances, therefore sacrificing defensive ability for offensive capability. Buffing this item requires for it to provide a bonus for melee-characters, so having it provide on-hit darkfire and maybe physical critchance (and maybe a small amount of resistances) in addition to it's current effects would be pretty good.
The Black Maul
Pretty good item as is. Good damage buff, the set buff is good too. Notably, this reduces the defensive abilities by not having the black spike and wall.
The Black Spike
This is pretty good as it is. It's not super incredible on it's own, but the set item bonus is really good. For some reason it provides resistances as well.
The Black Wall
Another perpetrator. This Item is not good. While having a good block value of 200, this item does not stand out in any way above other shields without the set bonus. Without the set bonus, this is worse than any generic shield, with the only unusual aspect being the relatively low base power darkness damage and relatively high defense value... on a set item for an armor focussed set. Without the set bonus it lacks any resistances. This is interesting as the sword actually provides resistances. The set bonus is mediocre. With 40 shadow power you can gain 16% all res. Certainly not bad, but not amazing either, given that this needs to compensate for the lack of resistances on all but 5 damage types. This needs a buff. I would suggest buffing the base item with some resistances, like physical resistance and increasing the set bonus factor from 0.4*shadowpower to 0.6. Remember: This is not for this item only, but for equipping the whole set, so it needs to compensate for it's lack of resistances.

What do you think? Does this sound sane? Do you have any critique or suggestions?

PS: The set provides an awful lot of singular category masteries. The shield and the black wall providing shield/2h specific category masteries, with the rest of the items providing seemingly random masteries for doombringer and demonologist. Just seems messy, not necessarily needing a change, but... damn, so messy.

[HousePet]

I agree with this thread in general, as I also never use the set, even when I played online so I could use the item vault to store pieces.

But I'm tired at the moment and don't have time to review the items or your suggestions.

[Phantomfrettchen]

Gigastar suggested to unify most of the masteries under a bonus to all corrupt categories at 0.1 mastery for each point of shadow power on the amulet. I would personally suggest to keep the 2h weapon masteries on the mace and the shield masteries on the shield, but that may be preference.

[Chronosplit]

I still say that we need The Black Gloves. Not just because it's the only major slot to not have a Shadow Power giving item, but because there's not really a shimmer to match the rest of the set should you want to only recieve flesh wounds for a run.

It doesn't need to be a high power item or anything though.