A huge Gear will be encountered at the end of the Stalactite Cave. Make sure Fei and Bart are on high levels (20-25), even though it still may be difficult win at that. Have Bart cast Wild Smile on Calamity, making it hard for him to hit you with any of his physical attacks. Next, hit him with all your ten point attacks, and save your energy until your Gear power is at level one. Use your best level one combos for both Fei and Bart, hopefully hurting the Huge gear. Keep in mind that Calamity has 2500 HP, and that it will take a while to wear him down. His missile attack will still hit you with 400 - 500 points of damage, not giving you much time to defeat him. Use Fei's Guided Shot as your last defense.