Most random and ridiculous guess ever because I looked at this for ages and kept thinking about cards.

A simple expression (It's a cheap tactic)
A double duet (Squall and Rinoa/ Seifer and Edea (which are won from Edea and Cid))
Four of the same (Each card is strong on one corner)
Alike in the set (As above)
At the top of the list (First cards you'd pick)
Except for the guardian (Sorceress' Knight - Seifer)
Who is eternal and lost (He isn't killed after several fights, but he never returns to the group)
He can break this clan (He's the only 'bad guy' in the player cards)

I did return to check by the way, but there was only one guess. It was wrong and had no reasoning to explain the logic so I waited for more attempts.