Quadruple Giga is Luka's most powerful skill, taught to him in Hellgondo on the night of his final camp by Alice. It is the second last technique that he learns hitherto (Chapter 1 and 2). Using the combined power of the Four Spirits, it was the famed skill that Heinrich used to defeat Black Alice.
It deals anywhere from 40,000-50,000 HP worth of damage, enough to finish off any opponent in one hit. The technique also only costs 1 SP, allowing it to be activated virtually at any time.
However, it has numerous drawbacks which make the skill nearly unusable:
1. It takes four turns to prepare.
2. If Luka is hit during any of these four turns of which it takes to prepare Quadruple Giga, the attack (Quadruple Giga) will be canceled.
3. All four Spirits are deactivated upon use.
Due to these flaws, Luka can only use the attack against four enemies in Chapter 2 of Monster Girl Quest.
- Imp: Imp does not know what’s going on and thus can be attacked with Quadruple Giga. If defeated with this technique, a defeat message saying "even her screams were sealed" will be shown across the screen. Using Quadruple Giga against the Imp is an overkill, and is there solely for the sake of humor, as well as video game cruelty potential.
- Tamamo (Second Battle): After using her Moonlight Cannon skill, Tamamo is exhausted and cannot continue the battle. Quadruple Giga can be used at this point.
- Granberia (Fourth Battle): She requests this skill be used in the final part of the battle. She will wait for Luka to prepare the attack, and she declares Luka's victory over her after this attack connects.
- Alice (Second Battle): After Alice's HP hits zero and she requests Luka to finish her, this attack can be used to finish her off. This leads to a little extra dialogue which includes Alice lamenting over Black Alice’s defeat by Heinrich.