Hey guys - I've got a thing going with a heretic (on his way to becoming a diabolist probably) in a game and I need a good latin translation for "I deny the existence of the Holy Spirit".
I'm 85% sure it should be Nego esse Spiritum Sanctum.
I think it should be: "(ego) nego essentiam Spiritus Sancti" or "(ego) nego veritatis Spiritus Sancti". I think "esse" is wrong because it's the infinitive form of the verb "to be" and I doubt it can be used as a substantive, especially as a direct object.
"Credo" is first person present tense.
I don't know if "existentia" exists as a word, but if it does, you should use the direct object form, which is "existentiam"
"Spiritus sancti" because it's genitive and spiritus is fourth declension, while sanctus is second declension masculine.
Another thought is maybe the thing to do is correct the "esse" infinitive. Thus "Nego est spiritus sancti".
I think that'd literally be "I deny the holy spirit is.", so that could be off. But I suppose that very well could be the idiomatically correct way to say it, though.
I think that a diabolist would:
a) Start with the standard Credo.
b) Prepend the negation NON, that negates all the following (so "Non credo ..." i.e. "I DON'T believe ...").
c) If in a hurry, snip all the part about the Father and the Son "... in unum Deum etc. etc." and jump immediately to the part about the Holy Spirit "... in Spiritum Sanctum".
This is 100% correct. It uses the construction ACI (accusativus cum infinitivo) which many modern languages don't know any more - but which is correct and even idiomatic in Latin.
Replacing the subordinate clause by a simple object is correct Latin, too.
It is just more vague and ambiguous: does your heretic deny/refute the relevance of the Holy Spirit for his sect/belief, or its existence?
Such ambiguity may be desired or not. It may actually be relevant in-game, when e. g. an inquisitor tries to figure out the specifics of an heretic sect's set of beliefs. Though, if it comes to that, agreeing on a plain English motto for your sect, that all the troupe understands without fiddling with Latin grammar, might have been better for the saga.