I was actually cooking up some individual element shields like that a while back, but also included matching Resist auras like Flickering Flame has. It was something like:
holy shield isnt busted only because of added block, its also reduced block frames to 2, or 1 and becuase fo the huge defense bonus
while level 3 is only 80 seconds
with extra 55% bonus defense
something like a necro or druid with 0 fbr going from 11 frame block to 2 frame still with 0, is absolutely absurd.
and dont underestimate defense, it doesn’t take much defense until enemy hits start to miss you, especially if you’re not in a terror zone
sure you probably wont reach 50% miss chance unless you go above 6k def
but free defense is free
Seems interesting! My mind immediately wonders what this would do for wind druid / lightning javazon.
Yeah, both fire and wind druids would get a buff. Vengeance paladins and Tesladins would get a buff. Javazons would like LM, but they arguably don’t need it. Heck, might even find use on the Enchantress. Would be really fun to test this runeword in the PTR.
Please consider adding negative affixes which affect only player characters (such as -Vitality, -Mana), to discourage using such an item instead of equipping hirelings.
If we did want to add a negative affix to discourage players from using runeword, adding minus mana would probably work best as Iron Wolves don’t use mana. We can add Prayer Aura to the runeword to add a source of healing to the merc for added survivability while also adding -50 to Mana as shown below. Updated OP.
Shield
Vex Ohm Lo
Required Level: 59
Level 9-12 Prayer Aura When Equipped
+200% Enhanced Defense
+1-3 To Fire Mastery
+1-3 To Cold Mastery
+1-3 To Lightning Mastery
+35-45% Faster Cast Rate
+5 To Max Fire Resist (Vex)
+5 to Max Cold Resist (Ohm)
+5 to Max Lightning Resist (Lo)
-50 to Mana
Changed name to “Piety,” thematic for prayer aura. Name is from unfinished runewords list.
Hey Charles, I like the idea of this purpose build Act 3 merc buff shield. We propably not seeing the proposed merc changes as well. But that would offer an easy alternative to the 2-3 adjusted uniques we made in the other thread and 2 OS “new” Splendor.
I think that shield would not cause to much of a problem given the fact that you sacrifice a lot in your shield slot by using this. But if we need that the -50 mana might not be enough? -250 would be a clear statement. What the game does if your base mana is below this 250 would be easy to figure out.
So I would support this overall!
Is this thread the discussion thread only for this shield and we collect maybe 2-3 other mid-game RW gabs in a “result” thread? Would like to discuss a mid lvl (25+/-) 3 OS 2H Staff RW for cold skills (in between OP Leaf and lvl 37 Memory). To make at least some use of a good staff mod rolled 3 OS staff (but not endgame viable)? 2OS Katars (+3/3/3) would get a good variant with a potentially buffed Wind RW.
I think the easiest avenue for the devs to take to buff Act 3 mercs is to add a new RW tailor made for them. I hope they consider more merc changes, but I’m not holding my breath.
I think -250 mana may be way too much of a penalty. For the lolz, we could have -89-112 To Mana to be opposite of Spirit bonus. 
I wanted to keep this thread dedicated to a shield for Iron Wolves as they really need the help. Feel free to add your RW ideas to our main thread, “Season 6 - Calling to Improve Itemization.” I can make a new section in that thread for RW ideas from the community.
Another justification for this new 3os shield runeword is the Iron Wolf is unable to natively reach the required STR to equip a Monarch for Spirit and has to wait to mid 90’s to have enough STR to equip an eth Monarch or equip gear with +strength, like Lionheart.
In a nutshell, this merc is completely useless until mid 90s to being borderline useless after getting enough strength. This merc is in a really tough spot with limited options when it comes to shields, which is the reason why this new runeword fixes many of these issues surrounding our elemental sorcerers.
actually it will be garbage for veng paladin,
prayer kinda useless
masteries useless
fcr useless
max resist okayish
there are many many other shields better than this for this build.
Maybe trash for veng pally, but do you think this shield would help make A3 merc viable?
I’m curious what you guys think about an alternate version of this shield RW. Instead of Prayer Aura, what about a Lvl 1-3 Conviction Aura, reduce masteries to static +1, increase negative affix to -100 Mana to discourage players from equipping, and then rename back to Wonder? 
Shield
Vex Ohm Lo
Required Level: 59
Level 1-3 Conviction Aura When Equipped
+200% Enhanced Defense
+1 To Fire Mastery
+1 To Cold Mastery
+1 To Lightning Mastery
+35-45% Faster Cast Rate
+5 To Max Fire Resist (Vex)
+5 to Max Cold Resist (Ohm)
+5 to Max Lightning Resist (Lo)
-100 to Mana
Not for such a price. Infinity is worth 2 HRs, whereas this Wonder 3 (lower than Infi, but still HRs).
Agreed. I would much rather have prayer on Act 3 merc so he can heal himself and the player. This would also be the first item to grant prayer, so special in that regard. Here was my thought on gearing the Iron Wolf…
Piety is interesting I won’t lie. Yet I find the following proposal for it to be better suited:
Piety
3 Socket Shields
Vex Ohm Lo
25% Chance to Cast level 20 Fade when struck
Level 9-12 Prayer Aura When Equipped(varies)
200% Enhanced Defense
+20% Increased Chance of Blocking
+20% Faster Hit Recovery
Magic Damage Reduced by 15
+5 Max Fire Resistance(Vex)
+5 Max Cold Resistance(Ohm)
+5 Max Lightning Resistance(Lo)
Requirements -40%
I tweaked Piety a bit by removing its Offensive attributes in favor of Defensive ones. This would discourage players from using this unless they truly wanted the Defensive benefits this runeword would provide them(not to mention having to overcome Prayer’s constant Mana Drain). The first tweak I made was removing the Mastery skills. These could be added to each Iron Wolf’s arsenal respectively as opposed to this runeword. In their place I added three Defensive attributes. I added +20% Increased Chance of Blocking since Act 3 Iron Wolves will need all the help they can get on this. I added -40% Requirements so that higher Strength Shields can be utilized(notably Aegis/Ward that have higher Block Chance rates). Then I added 25% Chance To Cast level 20 Fade when Struck. Fade is a very powerful Assassin buff that Act 3 Iron Wolves would truly benefit a lot from. It grants shorter curse duration(Merc’s can get wrecked after being cursed), 20% Physical Resistance(which is huge for Iron Wolves durability) and a big boost to their Resistance(+64 to be exact, taking advantage of Vex + Ohm + Lo perks).
I then removed the -50 to Mana malus since I thought it was unnecessary and instead added Magic Damage Reduced by 15. Considering Iron Wolves fight enemy casters, the attribute seemed fitting. I then removed the Faster Cast Rate attribute in lieu of Faster Hit Recovery(which Mercenaries can also use).
Admittedly, my proposal does come close to mirroring Sanctuary in certain respects but this costs way more and grants an aura that has a constant upkeep.
As for a A3 gear layout: Spirit Sword is still BiS for +Skills/FCR(why would they use Lawbringer…), Piety(Prayer + Defensive perks) for Shield, Flickering Flame(Fire)/Nightwing(Cold)/Griffons(Lightning) for Helm and Guardian Angel(Um’d) for Max Resistance and Blocking attributes in Chest Slot.
the mastery skills are the main component of that runeword though. point is to make it easier for the devs to implement that change. for some reason i got the feeling the devs wont balance the mercs a second time (though the only one really in need is the a3 merc)
I wanted to design a shield RW specifically designed to improve the viability of the Iron Wolves and have a feeling the devs will not touch them again. The masteries are vital to make that happen to improve their damage.
Also, as Iron Wolves can’t block w/ equipped shield due to lack of animations, adding +Increased Chance of Blocking only benefits players. I do like your idea though of adding minus req. as that could help STR problem and the MDR does seem fitting.
We could make it a 4os shield with adding a Hel Rune, that way we get req −15%, and replace the negative affix of -mana w/ your proposed Magic Damage Reduced by 15. Although, I do want to discourge players from using RW so the -mana works well, even adds a little flavor with showing act of penance (voluntary self-punishment).
So many possibilities. 
I’ve been thinking about this a bit and had some thoughts (lol).
For a penalty that would discourage player use but not harm Merc use, another option could be “-20% Blocking Chance”. That could offset some of the potential OPness for certain builds because it would require much higher Dex investment for blocking, but wouldn’t effect mercs at all.
Another thought was that, in addition to the -20% blocking, maybe this could become an armor RW instead, that way Act 1 Mercs could also gain Mastery? It would kinda be a like a reverse glass-cannon-ey Guardian Angel. For players it would compete with Enigma for the armor slot, but would be strong for Tesladins/Dreamadins, albeit at the cost of extra Dex needed for blocking which would make them more glass-cannon-ey if they used it (lower block or lower Vit).
I think the main problem with this runeword is it could potentially break javazons. Lightning mastery as o-skill and self-wield conviction aura could add power creep for the javazon, which is a bad thing.
This could be solved by having RW only have fire and cold mastery (remove lightning mastery). This shouldn’t be a problem as the merc has access to Cresant Moon, which has -35% enemy lightning resist. We can use DarkHelmets idea for adding MDR by replacing Lo rune with Mal rune, add minus requirements, and then remove lightning mastery. What do you guys think?
Shield
Vex Ohm Mal
Required Level: 59
Level 9-12 Prayer Aura When Equipped
+200% Enhanced Defense
+1-3 To Fire Mastery
+1-3 To Cold Mastery
+35-45% Faster Cast Rate
+5 To Max Fire Resist (Vex)
+5 to Max Cold Resist (Ohm)
Magic Damage Reduced By 7 (Mal)
-50 to Mana
Requirements -30%
Firstly, you can’t self-wield Infinity given it takes 2-Hand Polearms/Spears. Javazons could never wield it and Piety at same time so removing Lightning Mastery only serves to screw over Lightning Iron Wolves. Even so… Javazons would be more inclined to use Stormshield given its massive Physical Resistance, Phoenix for the Redemption aura or a Shield that grants gobs of Resistance(like Sanctuary or something along those lines) since the Helm is most likely Griffons for Lightning Damage + -Enemy Resistance(25% FCR doesn’t hurt either) while Chest slot is either Engima for mobility or CoH given the massive need for Resistance.
If Piety granted them Lightning Mastery as an O-Skill, I find that to be a welcomed addition since while that would indeed benefit them, the Fire O-Skill would benefit Fire Druids in the same manner(although that would be a tough choice given Phoenix and its -28% Enemy Fire Resistance occupies the same slot).
Anyways if you wanted to keep the Mastery O-Skills, I can’t object to that. I just felt they could be added to each Iron Wolf respectively and as for Blocking, they could be made to block, thereby making Blocking attributes extremely valuable.