Lunar Titan is an optional boss in Final Fantasy IV Advance and The Complete Collection. It is fought during Yang's Lunar Trial at the Lunar Ruins. When beaten, the player obtains the Martial Armlet, which changes Yang's Focus command to Deadly, and the Grimoire LT which, if used as an item, summons Lunar Titan to deal 9,999 damage to all ground enemies. Using up the Grimoire unlocks the trial door again.
Lunar Titan's physicals hit for over 1,000 damage, so healing often will be needed. Yang and Cecil should attack, while Rosa or Porom heal or cast Holy. Palom or Rydia should use Flare to pierce Lunar Titan's defenses, or use their special commands (Summon or Twin). Lunar Titan can also use Crush, which instantly kills a party member, Stone Gaze, which inflicts Petrify, and Earthquake which does mediocre damage, and can be avoided easily by casting Float.