Those creatures were the EMERALD WEAPON & the RUBY WEAPON , and yes they are both stronger than Sephiroth - Evan though he is the strongest being on the planet (NOT TRUE) - All of the weapons' are stronger than him.
I used KNIGHT OF THE ROUND to be BIZZARO SEPHIROTH , and then all my summons and level 3,4 5 spells (INCLUDING CURE,DE-SPELL, AND BARRIER)-To beat SAFFER SEPHIROTH - It took me a while to beat SAFFER SEPHIROTH.....BUT EVENTUALLY BEAT HIM
[ December 13, 2001: Message edited by: Mudokon101 ]