Giga Gaia will open with a triple tech Fire technique that hits your whole party, then a Shadow one next. Defeating one hand will put a stop to these attacks, at which point it may use a double tech that cuts a character's HP in half. The hands can also heal the head. The left hand is more vulnerable to magic with a higher physical defense, and the right hand is the opposite. The difference is not severe, so your best full-screen attacks should be effective regardless.

By itself, the head will do nothing but quietly count down to restore its hands. Depending on your level and gear, the hands' attacks may not feel particularly dangerous, but the animations can be time-consuming, so attacking with full-screen techniques until the hands are defeated is a good strategy. Then, unleash your best damage on the head until it revives the arms, and then repeat.

Giga Gaia is the final boss when playing in the Ice Age category, and its stats are adjusted to reflect this. The physical defense of the left hand and the magic defense of the right have been buffed, so full-screen damage of one type will be less effective. Because of this, you may choose to focus on one hand at a time if you want to get rid of them. If you decide you'd rather put up with its attacks, using Black or Red armor so that some characters can absorb the constant damage from those elements can be helpful.

The hands also have a Speed buff. The left has a Speed of 14 and the right has a Speed of 13.