Hmmmm...It's A Looong Time Since I Last Played Xenosaga III...If I'm Correct,Every Character Get A Last Ether(By Developing Ether Techniques,The Last Ones You Can Learn) And One Of Them I Think Made Your Ether And Techniques Cost 1 MP,Or Others Raised WAY TOO Much The Parameters During Battle,So Yes,Until You Get Them,You'll Have To Level Up A Lot...After Complting EVERY Sidequest Of The Game,I Remember They Were At Level 75-80,So Probably Level 67-70 Should Be Fine To Deal With Kaiser Sigma...Better Read Gamefaqs
