Dark Aeon The Dark Aeons are dark counterparts of aeons in " Final Fantasy X " . They are superboss es and one of the extra features included in the International , PAL , and " HD Remaster " versions of " Final Fantasy X " . Each has a red spot somewhere on their body and appear as darker - colored palette swaps of the aeons Yuna can summon . Though the possessed aeons during the final battles use the same models , they are not referred to as " Dark Aeons " . In the Japanese versions the enemies ' names are prefixed with " Heretic " , but the collective is still referred to as " Dark Aeons " in Japanese publications . List of Dark Aeons . Once Yuna and her guardians escape Bevelle Dark Aeons appear to halt their journey , some blocking access to previously friendly locations , while others wander in inconspicuous locations hoping party would come across their path . Returning to some of the previous locations is made impossible until the player defeats the Dark Aeon , which can make things tricky if the player did not obtain all items in these places yet , such as the hidden treasures in the Cloisters of Trials , the Sun Crest in Zanarkand Dome , or the second Overdrive for Valefor and the Jecht Sphere for Auron ' s Bushido in Besaid Village . Each Dark Aeon boasts a high HP , with Dark Anima taking the honors with eight million . They have supreme stats and are immune to status ailments . They drop weapons and armor with Break Damage Limit and Break HP Limit , along with other high - level auto - abilities , such as Ribbon . Some of the Dark Aeons ' abilities are non - elemental , such as Dark Shiva ' s Diamond Dust and Dark Ixion ' s Thundaja . Thus , Elemental - Eater abilities have no effect . Dark Valefor . Dark Valefor is available after escaping Bevelle and after the scene of Tidus and Yuna ' s underwater date . The player must walk all the way back to Besaid via Thunder Plains , cross the Moonflow on a shoopuf and take the ferry from Luca to Kilika and on to Besaid . At the entrance to Besaid Village , a summoner blocks the party ' s entry and summons Dark Valefor , who must be defeated to return to the village . The pre - and post - battle cutscenes use recycled dialogue from early parts of the game . If Valefor ' s second Overdrive , Energy Blast , was not obtained before the Dark Aeons spawn , the player will have to defeat Dark Valefor to obtain it . One of the Jecht Spheres Auron needs for his Bushido is located in Besaid Village . Unless the player makes a long trek back to Besaid after Jecht Spheres are unlocked , defeating Dark Valefor is the only way for Auron to learn all of his Overdrives . Dark Ifrit . After obtaining the airship , Dark Ifrit is found at the entrance to the now - inaccessible Home on Bikanel . If the player approaches the former entrance , a summoner disguised as an Al Bhed woman will ask for their assistance , luring them into a trap where Dark Ifrit pounces if they try to peer over the edge of the canyon . The appearance of Dark Ifrit relates to the Home glitch that affects some International versions . Dark Ixion . Dark Ixion is available after viewing the arrival cutscene of Calm Lands . The first battle against Dark Ixion will initiate after talking to the Warrior Monk in the northern area of the Thunder Plains . Dark Ixion must be defeated twice before he will disappear and the player can escape the battle . The second battle with Dark Ixion can be avoided until the player is ready , allowing for items to be restocked . Dark Ixion uses different attacks between the first and second battle . Dark Shiva . Dark Shiva blocks the entrance to Macalania Temple and is summoned by a group of Guado . Once she is defeated , the Guado will chase the party away from the temple , like they did after the defeat of Seymour Guado . After the party escapes , it is again possible to return to the temple . Dark Bahamut . After defeating Yunalesca and obtaining the airship , Dark Bahamut takes her place in the Zanarkand Dome . If the Sun Crest was not obtained before embarking on the airship , the only way to get it is by defeating Dark Bahamut . Dark Anima . If the player returns to Mt . Gagazet after viewing the campfire scene at start of Zanarkand Ruins , and then completes Wakka ' s ball - throwing trial in the mountain cave once more , Dark Anima will appear at the entrance to the mountain . The party is not forced to fight Anima , so she can be spawned and then left alone until the player is ready . Dark Yojimbo . Leaving and reentering the Cavern of the Stolen Fayth after completing its events will summon Dark Yojimbo to ambush the party . After his first defeat , the summoner will retreat through the cavern , and the next battle will initiate upon their next encounter . Dark Yojimbo must be fought five times in a row for him to be truly defeated . Returning to the save sphere to replenish the party ' s HP and MP and to save the game will not reset Dark Yojimbo ' s battle count , but if the player reloads their saved game using the soft reset , enters the blitzball menu , or leaves the cavern , the battle count is reset and the player must start over from the first Dark Yojimbo fight . This can be used to the player ' s advantage to fight him repeatedly to obtain the drops . Dark Magus Sisters . After obtaining the airship , the Dark Magus Sisters are found on the Mushroom Rock Road , near the exit to the Mi ' ihen Highroad , and can be fought together or separately . Once the Dark Magus Sisters are summoned , they will approach the party , and if they catch them , a battle against all three sisters will initiate with their Overdrive bar full . If the player avoids them and runs towards the valley , the Dark Magus Sisters will give chase . If the player reaches halfway up the valley , Dark Cindy will give up , and if the remaining two sisters catch the party , Dark Cindy will not participate and will be fought separately . If the player reaches the mushroom elevator at the north end of the valley , Dark Mindy will give up the chase , and the player will face Dark Sandy on her own . Once Dark Sandy is defeated , the player must take the elevator back to battle Dark Mindy , and run back through the valley to fight Dark Cindy . Fighting the three Dark Magus Sisters separately has many advantages , as the player can heal between battles , and the sisters cannot use their Delta Attack Overdrive , using Mega - Graviton instead . The Dark Magus Sisters can be evaded by reaching the save sphere , saving and soft resetting . Upon reloading the game Mushroom Rock can be traversed through as normal unless the player runs into the summoners again . Penance . Once the player defeats the Dark Aeons , Penance will appear as an option on the destination selection screen on the " Fahrenheit " . It is a superboss unrelated to the Dark Aeons that boasts 12 , 000 , 000 HP for the main body , and 500 , 000 HP for the arms . Etymology . The word " dark " means " lacking or having very little light or color " , as well being another way of saying " evil " .