i believe SIN arose out of the ashes of Zanerkand after Penance had destroyed it and knocked penance flying. without penance, beville was at SIN,S mercy until, as you know, yunalesca offered to defeat sin with her husband.

i know u think sin could never touch penance, but sin used his most powerful attack(u know, that move when u fight sin and dont beat him fast enough, its game over regardless and strongest move in the game).