Final Fantasy IV: The After Years

If you equip the Cursed Ring and a set of armor that offers elemental protection. You will now absorb the damage from that element at the cost of reducing your physical defense. For example, when used with the Dragon and Crystal Armor it will absorb all elements.

Cast the Blink spell (White Magic) on your characters to have them immune to physical damage for a short amount of time. Rosa, Kain, Ceodore, and Fusoya can cast Blink.

Successfully complete the game. Load the cleared game file and continue the game. Go to Namingway to play new challenge dungeons. There is one for both the base game and Rydia's Tale.

Defeat the Lunar Dragon in the Lair of the Father B3 in the Subterrane. Next, have Palom, Porom, or Leonora learn Dualcast. Leonora is recommended as she gets Black and White magic and is a better White mage than Porom. Place the character that learned Dualcast in the party and start a battle.

Use the Stone Blade, Medusa Arrows, or other weapons that can cause the enemy to slowly petrify.