The Arcana Ruins (アルカナルイン Arukanaruin?) are the EX Dungeon of the PlayStation 2 remake of Tales of Destiny. Located in the ruins of an ancient temple near Janos in Phandaria, the dungeon is comprised of ten floors ridden with puzzles, with one final room for the last boss of the dungeon. The Arcana Ruins replaces the Tower of Druaga which was present at the same location in the original release of Tales of Destiny.
After loading a clear save file for the current playthrough, the clown Cyglorg will appear next to the door leading to the final boss room. Upon speaking to him, Cyglorg will tell the party to meet him at the location where Rutee Katrea had been trapped near the beginning of the game. From there, Cyglorg will give an explanation of the dungeon and then teleport the party inside. If the clear save file is for "Leon Side" in Tales of Destiny: Director's Cut, Cyglorg will appear near the final save point of the Underwater Cave near Libra IV and teleport Leon Magnus into a warp room which includes the Arcana Ruins as one of four locations that Leon may explore, since he lacks the abiltiy to exit the Underwater Cave by any other means.
The Arcana Ruins features many enemies and items that cannot be found elsewhere in the game, such as the special sphere items used to re-rise the most powerful equipment in the game, though their placement is randomized and limited to one per floor, with duplicate item placement being possible on multiple floors. This dungeon also provides the most reliable source of the rarest types of Lens. All of the treasure chests within the dungeon, varying in color, cast beneficial or harmful effects on the party when opened. Any battle-consumable items owned by the party will be disabled when entering the dungeon; only the items that are dropped by enemies or treasure chests within the dungeon may be used. Out-of-battle consumable items such as Holy Bottles and Oberonamin medicines can be brought into the dungeon and used without any penalty. In the Director's Cut, it is possible to purchase a bag of items containing a small quantity of consumable items for battle, which may be brought into the dungeon. The Gald price of these bags is exorbitant and far exceeds the net value of the items themselves.
The dungeon limits the player regarding how often party members are able to be taken on each floor during a single run through the dungeon. Each party member may enter a floor up to six times, except for Lilith Aileron, who may only enter up to four times. Party composition becomes an added challenge, since a maximum of five party members may be chosen per floor, one of which is set in reserve for his or her passive support talent and cannot be switched into the active battle party. Party membership must be rationed equally to prevent any desired characters from being locked out of later dungeon floors. Enemies on a given floor tend to share a common weakness, making certain characters more useful to add to the party during that floor to exploit "Weak Point" damage chaining and enable the player to have the best luck in completing the dungeon. Certain floors also share common Definite Strike character requirements, again emphasizing the utility of certain characters on specific floors.
If any character is knocked out during battle and does not get revived before the end of that battle, that character is removed from the party, forcing the remaining party members to continue the floor without that character. Furthermore, equipped items cannot be removed from characters who are not in the party, meaning any important accessories must be removed before changing the party composition for the next floor. Note that the use of Narikiri Dolls may be used to circumvent the limitations on character use throughout the dungeon, since only the base character is counted for this purpose.
Each floor has an enemy encounter that acts as a floor guardian. This encounter is represented by a visible creature token on the field. It is impossible to move to the next floor unless this encounter is defeated, after which a new warp point is spawned somewhere on the floor. This enemy encounter may consist of a group of normal enemies from the same floor, or a single boss enemy such as Finley Doug or KOKU-MOTSU. Additionally, one of the floor guardian enemies, the Mofuriina (もふりーな?), has a small chance to spawn during any random enemy encounter as a reinforcement anywhere within the dungeon.
One of the main objectives of the dungeon is the acquisition of "EX Points", which are earned from battles, treasure chests, and floor completion. These points can be traded to Cyglorg for unique items such as the Narikiri Dolls. More EX Points are earned if there are less party members that complete a given floor, with the greatest earnings possible with a party of only one character. A full party wipe within the dungeon forfeits all points earned, but it will not count as a game over; the party will simply teleport back to Cyglorg upon defeat, with all earned experience and items intact. Saving the game is possible when transitioning between each floor, at the cost of EX Points. It is also possible to exit the dungeon at any floor warp point without penalty, unless the player saves at the final warp point on the tenth floor, which renders it impossible to retreat from the dungeon. Barbatos Goetia serves as the final boss of the dungeon, located and fought after completing the tenth floor. The party composition cannot be changed during the transition from the tenth floor to the final room, so the selected party for the tenth floor must be the intended party to challenge Barbatos.
Due to the timeline of events that enable exploration of the Arcana Ruins on "Leon Side" in the Director's Cut, certain things are altered. Garr Kelvin cannot use Swordian Igtenos since the Swordian will not be repaired until the facilities at Helraios are accessible. Because of this, Garr will use the "Royal Blade" weapon during battle, regardless of if he is chosen as the actual character or another character with Garr's Narikiri Doll. As a result, Garr cannot access his Swordian Device, preventing the use of any passive skills offered through that system, and his damage output and Chain Capacity range is limited to the stats of his weapon. In contrast, Leon Magnus may now access his own Swordian Device, which is not possible for any other character using Leon's Narikiri Doll. Since the Director's Cut globally modifies Holy Bottles to reduce enemy encounter rates to zero, it becomes much easier to clear the dungeon by avoiding random encounters entirely. However, the party experience levels are significantly lower compared to the achievable levels of "Stahn Side" by the time the party can unlock this dungeon. Equipment availability is also poor on "Leon Side" until enough EX Points can be earned to purchase relevant items.