I think it is more likely to be an alt of Sirius or at least someone who is known to him. Sirius is the co-founder of the the forum and used to control the domain. It is likely that he doesn't want to be hassled so transferred it to an anonymous alt or someone he trusts.
I also reached to the same conclusion on my earlier post.
Unfortunately, Nobody took interest/notice on it.
But there some interesting post by Theymos itself in 2014.
Theymos also claimed that he do not know this anonymous person.
I don't know his identity, and it was clear that he didn't want his identity to be known.
In short, not only the creator of Bitcoin is anonymous but now also the domain owner of this forum.