Been doing some in game reading and from what it seems like to me Sithis is more powerful than a daedric prince. It doesn't actually say it but I get the feeling bethesda is about to do something huge involving him. Other than that does anyone think he is more powerful than the princes?

The Daedric Princes seem to be like demi-gods because they don't seem to have enough power to operate wherever they want. They always have to get us to do something for them because they seem to have little to no power outside of Oblivion. From what I've read I don't think Sithis is a Daedric Prince, but I've never heard of him doing anything god-like within one of the games. Surely someone who knows the lore can clarify.

Sithis is a nonsentient force of nature.

Sithis is basically nothingness. He may be more powerful than a prince, but he has no direction nor cause to do anything. Does a Hurricane choose where it lands, who it saves, and what it destroys? The answer is "no."

And this is the ultimate insanity of the Dark Brotherhood. They worship something that doesn't know it exists, that they exist, and that even if it did, wouldn't care. If gamesas is planning something with Sithis (which is unlikely, since the Dark brotherhood isn't a major facet of Oblivion and Skyrim) it'll be a side-effect of whatever the Thalmor are planning.

In the book The Night Mother Truth it says that Sithis speaks through the "undead" (don't know what to consider her) Night Mother. Thaats how she even came to be the Night Mother of the Brotherhood.

You may be interested in http://www.uesp.net/wiki/Lore:The_Monomyth and http://www.imperial-library.info/content/childrens-anuad.

Thanks

From What I gather, it's thought that Sithis is Padomay? one of the two twins that created the Aedra and Daedra, and brought Lorkhan into being, which resulted in the Creation of Mortals