A proposed house rule for might strippers, because these are too powerful IMO, even in a non high-powered campain:
Critters have a "soak" versus might strippers of (Might score)/4
Thus, a might 20 demon will be invulnerable to a multicast lvl 05 DEO, which would have destroyed him instantly under the RAW.
This, IMO, helps to keep the RAW guidelines about what is powerful and dangerous consistent.
What do you think of it?
Divide by 5 seems more mechanically appropriate. What about calling this a power which some have and some don't?
Since I'm still not that familiar with how 5e magic/magical combat works, I'd like to throw out a theoretical, see if I'm understanding correct (or, if not, where my flaw lies).
Cygna pulls out out her Wand of Demon's Eternal Oblivion (Level 25, +20 Penetration) and uses it against the hypothetical Might 20 Demon. With the house rule of "Soak" = Might/5, he has a Soak of 4, which would be applied to the Level of the DEO (which is also how much "damage" it does to his might, if I understand correctly). He also has MR = 20, his Might. Isn't that almost double-dipping, in a way?
Regardless: To determine if the DEO affects him in the first place, would I compare the level of the spell to his might? Or the level + Penetration? (I think the spell would affect him either way, as the level of the spell is higher than his Might, but with all the fooferall over on the main forums about penetration and wards/Aegis, it got me doubting). I don't think it matters in this particular case, but it might if we were to come across a demon with Might > 25.
After Cygna finishes her conversation with Viscaria, the night they arrived in Cijara, she returns to her temporary bedroom, and falls into a deep sleep. She dreams she is in her Memory Palace, fighting a Might 20 demon, played by Fixer. This demon is endowed with a mysterious new might-soak power, putting Cygna's Wand of Demon's Eternal Oblivion (Level 25, +20 Penetration) to the test!
The magi of Riversedge are watching, along with Amos.
This is only a dream, but it will prove to be a good test of the PbP battle system, all the same.
The dream begins with Cygna standing in front of the Phoenix tapestry, studying it intently. She looks to her right to see her former sodales sitting around the gameboard that represents the Iberian tribunal, all of whom are facing her. Grus and Vucar are seated next to each other, close enough that their knees touch, and they are self-consciously not holding hands (barely). Petros has an almost bored look on his face, while Cahira looks impatient. All four are watching her intently, studying her. Amos is standing in the corner behind them, looking rather nervous.
Before Cygna can ask them why they're here, she hears a scurrying, skittering noise behind her. As she turns around, the shadows around the Adorjan crucifix flow onto the floor, where they pool and rise up to take the form of a large, horned, cloven-hoofed man with glowing eyes. The demon looks around and then focuses his attention on Cygna.
She reaches into her robe and pulls out the Wand of Demon's Eternal Oblivion. Leveling it at the demon, she yells, [color=red]"Fúngere!"
(ooc - I don't think I need to roll for anything here, but I'm not sure)
OOC - This is an excuse for me to test out the combat system, which I have never used before, tabletop or PbP. We're also using it to test out the proposal by Fixer for the Might-Stripping Soak, so your first demonic opponent has that power. So....I believe the first step is, roll for initiative?
Ah. Right. Initiative: Qui 1 + Stress Die 3 = 4. I couldn't find anything about whether Finesse gets added to this, but I don't think it does in 5e (might have in 4e, iirc).
I LOVE the idea.
But it's a bad exemple, as seen below.
We can see it through, though, since it makes a slight difference.
It's a whole lot easier.
/4 makes a difference for high might, though, but for our power level, this is negligible.
Well, your might 20 demon loses 25-4 = 21.
A might 25... If it penetrates (roll of 5+), the rules makes all the difference, by giving him the short edge he might need to flee. But this is a VERY bad exemple, since you're using a powerful spell without multicast, while the proposal is aimed at weak spells with multicast.
On the other hand, this makes Cygna's item (with level > Pen) a good idea.
To affect something, anything, you must beat its MR. This is RAW, but is where those discussions about wards comes from, since this makes wards vs creatures a harder and harder compared to DEO and such as might increases: Some people thus prefer their wards not to penetrate.
So, to affect a might 20 demon, you need a spell with enough penetration.
The problem being in short that critters are VERY vulnerable to the combo of might-strippers + multicast: 4 multicast pilum of fire (a lvl 20 spell!!!) might not be enough against a might 20 demon, even if they have enough penetration. 4 lvl 5 DEO will do the job nicely. If you read the boards, the demonstration has been made time and time again.
For exemple, with a dice roll of 5+, to cast a lvl 25 might stripper with pen 25, you need, for exemple, Perdo 20, Vim 20, Pen 05.
You can do the same thing with, say, a might 10 stripper, Perdo 13, Vim 12, Pen 03, mastery 02.
Or a might 05 stripper, Perdo 10, Vim 09, Pen 02, Mastery 04.
By the RAW, these will work equally against a might 25 beastie.
This lessen that problem somewhat: With the "soak", against a might 25 demon:
Okay, so in the case of magic items, the Penetration is Stress Die + Penetration, then? So, since the Demon only has a MM of 20 (the same as the Penetration), it only fails to go through if the roll botches? Check that...just checked again, the Penetration Total has to exceed Magic Resistance. So, since MR = MM, then the Penetration Total has to be more than 20 (at least on the first shot). So, since the die roll is a 3, the DEO penetrates the demon's MR. And, since it's a level 25 spell, it shreds 25 (less 4 for the Soak, so 21) of the demon's 20 Magic Might. So, since it now has negative Might, it's dispelled?
Yup, exactly. For cygna, this makes little difference, the demon is destroyed the same way.
The only thing I'm not sure of is if DEO doesn't attack might pool before might score, which might give critters a little more time to flee.
Note that this makes items like yours, with a level slightly higher than penetration, all the more clever: If you had a lvl 20/ pen 20, the demon would have survived your first strike (albeit barely).
I checked the Errata, and DEO should affect Might Score. ("Demon's Eternal Oblivion (p. 160): Add "Score" after "Might". ")
Have we reached an accord?
I think so. And this applies to all creatures with Might, right? Including, oh, say...ghosts? So, if she were to cast her Lay to Rest the Haunting Spirit on an unruly spirit, she would have to first have her Penetration exceed the MR (Might Score) of the spirit. If so, then the spirit loses 20-(Might Score/5) Might points. If I understand correctly.
(sorry, haven't played much 5e before, so this is kinda new to me. And I'm more of a learn-by-doing than a learn-by-reading kind of person)
Me too, which is why I wanted you two to RP a fight.
Thanks for checking.
Exactly.
I'm happy we agree on this 
. These spells + multicast are still powerful, but slightly less so, which, IMO, is good for the setting, dragons and faerie lords.