Do the symbols that appear in the OP of Sasami-san@Ganbaranai mean anything?
The characters look very similar to Jindai moji (Encyclopedia of Shinto link) (Japanese Wikipedia link). 


(Image taken from Talk:Jindai moji page on Wikipedia)

These characters are theorized to have been Japan's character system before Chinese characters were introduced.

If I go through that table for the first image you show and match the characters (with help from the matching done by the article that @senshin posted), that gives me

ツ(tsu) ヰ(wi)  ヲ(wo)  ソ(so) マ(ma) ？     カ(ka) 〜      エ(e)
ノ(no)  ゴ(go)  ト(to)  ハ(ha) ア(a)  ク(ku) テ(te) ロ(ro)  コ(ko)
エ(r)   タ(ta)  ナ(na)  ソ(so) ル(ru) イ(i)  ア(a)  シ(shi) サ(sa)
サ(sa)  メ(me)  ゴ(go)  ハ(ha) ク(ku) ロ(ro) フ(fu) ツ(tsu) ヲ(wo)
リ(ri)  ヰ(wi)  ソ(so)  ？     〜     ミ(mi) ス(su) ウ(u)   ガ(gu)


My Japanese is not very strong, but I don't get any relevant results when looking any consecutive substrings of those characters up on Jisho (a Japanese-English online dictionary) or Google Translate. 

I don't believe that the characters have any special meaning here.