also probability and fate hax would prevent the chances of madness even happening, not sure how it works but as long as its passive its fine
I believe you are refering to the
Auspice power, right?
Auspice does not interact with Resistance checks, what it does it is making the user succeed in every skill check as long: a) it does not involve knowledge, b) the difficult to meet is not Inhuman or Zen, and c) is not opposed to another action. In case its an opposed action (that also involves combat), the user will receive a bonus to every action against its target, depending of the Gnosis difference between both fighters.
Now, I don't have much to say about the entire madness thing debating; personally I think madness is madness, a mental induced, regardless of the method used. Although, depending of the nature of the power itself then a different resistance may be used: as a mental inducement, the Psychic Resistance (PsR) is the one used, but is also possible that Magic Resistance (MR) and Physical Resistance (PhR) can be used as well. For example,
Dementia (as well as few others entities without sheets, like the ginnungaus) madness inducement is a MR check, so mental fortitude has no room in this as it depends more of the Presence and Soul of the affected one. Meanwhile, Zemial's
Blood of Insanity uses Venom Resistance (VR) to avoid its effects, so neither the soul or willpower are relevant here.
As for Ergo's layers, just as we agreed in the Layer thread, every +5 above 20 is a layer, and Ergo has a PhR, MR and PsR equal to 140, 160 and 140, respectively, meaning that his layers are 24, 28 and 24 (although, if you are familiarized with Anima, you will notice that those numbers do not fit, because considering his CON, POW and WIL values, his resistances should be more 145, 150 and 135 respectively. I, however, will not argue whenever the author forgot to write potential bonuses/penalties to resistances, or these values are slightly mistaken). Those are Ergo's base resistances, and he may increase them through to use of spells or by mimicrying other monster's powers).