Adamantoise gains a level every two times it is defeated, up to a maximum level of six after being defeated ten times. Adamantoise is considered to be one of the most dangerous opponents in Dimensions.
Adamantoise uses several familiar attacks from various enemies but with much higher damage such as Carapace, Bite and Quake. It can also use Roar to Stun a target and Brain Crush to inflict Berserk and Confuse to an ally, not to mention Bite can cause Poison and Confuse. It most powerful attack is Temblor, which is twice as powerful as Quake.
As a superboss, the enemy cannot be vanquished without proper setup of offensive, supportive and curative party members. The enemy usually combines two moves, including his physical attack, Carapace and Bite, to damage the party. One member with high DEF and HP should make use of Draw Attack to focus the attacks on self and avoid Magus or Seer. Bite can inflict Poison and Confuse so it's better equip the character with Heroic Shield or Ribbon. Quake deals a moderate amount of damage and if Adamantoise's level is high enough, it will probably kill any character with low HP if not protected. Mighty Guard, Mighty Wall and double-casting Protect and Shell provides the essential defense against his attacks. After his HP drops below 50%, he starts using Temblor, which is twice as powerful as Quake. It deals massive damage and when Adamantoise's level is high, Temblor is an instant kill to any Magus, Seer, Bard or any low-HP character, even with Shell. However, Adamantoise will take longer than usual to make the next move after casting Temblor, which is enough time to revive all fallen members.
Final Heaven and Double-casting Meteor with Magic Font are among the most effective ways of damaging this foe. Phantom Rush, Midareyuki and Spreadshot may be useful of the enemy's level is low but will deal less and less damage as its level grows. The enemy may counter a magic attack with Brain Crush and physical attack with Bite (the non-status version). Remember to bring along some Remedies or X-Potions in advance.
White Wind and Full Cure are some great healing abilities, but double-casting Curaga, Healing Horn or Espilia with work just fine. Mega Raise is a great revival ability and may come in handy, but it's better to be put on a character with high HP as a mighty Temblor may KO any low-HP one.
The fight with a high-level Adamantoise can be problematic, especially after his HP drops under 50%. Unlike the other superbosses, fighting with this foe involves dealing with several negative statues. However, with proper party setup, even the max level Adamantoise fight will not be very difficult.
Adamantoise is a portmanteau of "adamantite" and "tortoise".
Adamantite and similar words including Adamant and Adamantine are used to refer to any especially hard substance, whether composed of diamond, some other gemstone, or some type of metal.