The Arsenal/Last Defense System is the catacylsmic final boss of SaGa II/Final Fantasy Legend II and SaGa 2: Hihou Densetsu: Goddess of Destiny. It is a powerful ancient security-system that was activated by Apollo's abuse of Relics/Magi.
The Arsenal is a large, spaceship like contraption designed purely with power in mind. It's got multiple wings and cables around it, and what seem to be screens showing lines of code. Alongside these supportive gadgets, the Arsenal is installed with four exterior cannons, and one interior, more powerful cannon, the Smasher, which is only activated after the first former are destroyed.
The Arsenal has three phases, signaled by the three main battle tracks that play in each one. In the first phase, Dreadful Fight plays, as the Arsenal uses four exterior cannons, attacking all party members. When damaging the Arsenal, the four cannons gradually get destroyed, one by one, and will start to get repaired if the player does not deal enough damage. As the cannons are destroyed, the amount of damage they deal to the party is significantly reduced. Once all of them are destroyed, Lethal Strike plays, as the Arsenal begins to activate the Smasher, exclusively on one character. Yet again, as the party deals enough damage, the battle reaches it's last phase, where Save the World begins to play, and the Arsenal fully launches the Smasher, attacking every party member with an insane amount of damage. But alas, as the Arsenal is finally destroyed, and so is it's twin brotherin by the godess Isis, the fight ends, and so does the party's tale.