Equip yourself with items that boost your defense or your health. That way, if you don't have the ultima weapon yet, you'll still have decent magic and attack power.
What level should I be to fight Sephiroth Kingdom Hearts? Sephiroth is considered to be among the most powerful villains in Kingdom Hearts series as well as among the most difficult bosses in all the times he is fought as a boss, with his boss fight in Kingdom Hearts rivaling Kurt Zisa and Phantom and ranking below only the Lingering Will in Kingdom Hearts II. That is the recommended level for that world. The World That Never was like other levels in KH2 has a battle level, and that is 50. I think you already know this, but the playable Roxas boss fight is one the new additions coming with the Final Mix version of KH2. What level should you be to beat Roxas KH2?