Lunar Asura is an optional boss in the Advance version of Final Fantasy IV. It is fought during Rosa's Lunar Trial at the Lunar Ruins. When beaten, depending on whether the player heals all fourteen people in the trial, the player obtains the White Ring, which changes Rosa's Pray command to Miracle, and the Grimoire LA which, if used as an item, summons Lunar Asura to deal 9,999 damage to all enemies. Using up the Grimoire unlocks the trial door again.
Lunar Asura uses Blizzaga, Firaga, and Thundaga to do heavy damage, and also casts Mini and Toad. She also often casts Curaga on herself like her counterpart, but also uses Restore to heal herself for 9,999. Rosa should cast Reflect on Lunar Asura to reflect her curative spells while physical fighters pummel her. Casting Reflect on the party can also help block Asura's attacks.