The Stormfather, Everstorm, and the Unmade.

[Radiant_Jaeger]

The Everstorm has come. We see in Words of Radiance that the stormfather says "They call for a storm. My opposite. Deadly." My theory is this. That opposite is to Odium as the Stormfather is to Honor(Tanavast) A new godspren but of Odium rather than Honor.

The voidspren that bring stormform could be to the Everstorm as Syl and the honorspren are to the Stormfather. I was also wondering what exactly the Unmade are. I would think that they have something to do with the Voidbringers because for Moelach telling the future is of the voidbringers. The thrill or nergaoul is another. Do these forces each have opposites? Are they of Odium or Honor or something else?

 

[The One Who Connects]

Well, the Unmade are Splinters of Odium. I have no idea if they have opposites, but they are entirely of Odium due to their Splinter status.
Foretelling the future is "of the Voidbringers" because the Sunmaker said so. It was more than likely not looked at in that way prior to the Heirocracy.
I do not have a source on when the Unmade were.. made. It could have been around Hierocracy times, but I personally feel like it should have been earlier.

I feel like Odium should've already had a Godspren by being in the Roshar system, perhaps it was trapped on Braize until the Parshendi summoned the Everstorm..?

Also: Ah, so that is where you got the Everstorm/Stormfather opposites idea. Must've missed that line when I last read the book.

[Radiant_Jaeger]

Re-Shephir, the Midnight Mother, giving birth to abominations with her essence so dark, so terrible, so consuming. She is here! She watches me die!

Another Unmade. I have a feeling that for each unmade there is an opposite of cultivation or Honor. Whether these be specific singular entities like the stormfather I don't know because Mr. T references how "The Unmade are a deviation, a flair, a conundrum that may not be worth your time. You cannot help but think of them. They are fascinating. Many are mindless. Like the spren of human emotions, only much more nasty. I do believe a few can think, however."  This makes me think that the Unmade who can think are like the Stormfather and Nightmother. and to a lesser degree Syl and Wyndle. Syl is a part of Stormfather just as he is part of Honor. Stormform is a part of everstorm as it is part of odium. Equal and Opposite reactions

[The One Who Connects]

Re-Shephir, Sja-Anat and Dai-Gonarthis have not yet been confirmed to be Unmade. It's assumed, but until there is a confirmation it's best to be wary.
I also believe Syl's relation to the Stormfather is a special case due to the circumstances surrounding Tanavast's Cognitive Shadow.