Oh, okay. I see. Everything that happened in the second half of the first episode makes more sense now. Sasami’s brother holds the power of Amaterasu, a major deity of Shinto religion. God(dess) of the sun (and whole universe, apparently) who commands all other gods. And because Amaterasu is in Kamiomi, everything bends to match his view of the world… whether he’s consciously aware… I don’t know. Doesn’t look like it.
That’s also the reason why Sasami has him under surveillance twenty four hours a day.
Next is to know who the Yagami sisters really are… going by the god theme, I’m guessing Onmyouji.