Yuna gains new Aeons when she prays to a Fayth in the temples scattered across Spira. You obtain most of them through the main story, but there are also 3 hidden Aeons for you to find.
In this guide, I am going to explain where you can find these hidden Aeons and what you need to do to obtain them.
For the trophy hunters amongst you, there are four trophies relating to these Aeons. Obtaining Yojimbo gives you the ‘It’s All About The Money’ trophy, obtaining Anima gives you the ‘Feel The Pain’ trophy and obtaining Magus Sisters will get you the ‘Delta Attack!’ trophy. Once you have collected all of the Aeons in the game, you will get the ‘Summon Master’ trophy.
His Fayth is located in the Cavern of the Stolen Fayth. This is found between the Calm Lands and Mt Gagazet. Remember the Guado that approach you as you leave the Calm Lands? There is a path to the right of there which leads to this cavern.
Proceed to the end of the cave and defeat any enemies you come across. You will then be able to enter the Chamber of the Fayth.
First, when you approach the Fayth, you will be asked what you want of him. Once you make this choice it cannot be undone. I would recommend choosing ‘To defeat the most powerful of enemies’.
One reason for that choice is that, unlike other Aeons, you have to offer a large amount to gil to the Fayth to get Yojimbo. Choosing the third option has the lowest starting price, which is 250,000 gil. You can haggle with him three times to make it cheaper however.
To make him as cheap as possible, offer him half of his asking price + 1 gil. So, start with 125,001 and then 112,501. This will bring the price down to 202,500. This is where I left it, but on the third attempt, if you offer him 141,750 this will apparently bring his asking price down to 190,350. (See here for the calculations behind it all.)
Yojimbo is also different to other Aeons in battle. His attacks are random and depend on your compatibility with him. There are some complicated-looking calculations on his compatibility, but it comes down to a few things.
Firstly: how much you pay him. For him to attack on a turn, you must offer him gil. He is more likely to perform better attacks as you pay him more gil.
His compatibility with you also improves in time with the attacks he uses.
Dismissing him immediately, paying him 0 gil or letting him die in battle severely damages his compatibility with you. If he has his companion Daigoro attack, that also slightly damages your compatibility. On the other hand, when he uses Zanmato or Wakizashi, it improves. His Kozuka attack doesn’t affect it. Use him in battle often against easier enemies to make sure he has a chance of winning and improving your compatibility.
The best move Yojimbo has is Zanmato. This instantly KO’s all enemies on the field, including the very tough Dark Aeons. If you maintain good compatibility with Yojimbo, he has more chance of using Zanmato. The probability of using Zanmato is also much higher when his overdrive gauge is full.
You will first encounter Anima in Luca and then several times throughout the story. Anima has an interesting back story and is one of my favourite Aeons in the game.
You can only obtain Anima once you have access to the airship. To find the fayth, search on the airship map around co-ordinates X=11-16, Y=57-63. This will give you access to Baaj Temple. You may recognise this place.
To gain access to the temple itself, you must defeat Geosgaeno. This is an underwater battle so you will only be able to use Tidus, Rikku and Wakka. He isn’t too difficult, but attacks with Stone Punch. If you cannot evade or resist this move, the battle will be over pretty quickly. I had Evade & Counter equipped, which made it an easy battle.
Once inside the temple, you will have a cloister of sorts to pass before you can access the Fayth. You must activate a glyph for each temple you have already visited. To do this, you must find the hidden treasure chest in each temple’s Cloister of Trials.
I highly recommend finding these chests the first time you visit each temple. This is because you cannot easily access the temples once you have the airship, due to the Dark Aeons blocking several of them later in the game.
I think the easiest way for you to see how to get these hidden chests is via Youtube videos. Thanks to Jarkeva for the straightforward videos below.
The chest in Bevelle’s temple is located just before the end of the Trials. You don’t need to do anything fancy to get this one, just make sure you get it because you can’t come back.
The final temple is the temple in Zanarkand. You cannot get the chest the first time you visit, instead you must return once you have gained the airship. As with the Trials the first time around, you have to stand on the correct shapes on the tiled floor. All you need to find is 7 squares (2×2) in the two rooms. The destruction sphere will appear once you have done this. Simply take it and place it in the recess to the right of the screen in the larger room to reveal the chest.
If you have missed any, you can revisit all of them except Bevelle, but you will probably have to get past a Dark Aeon or two. These are very tough. If you have missed Bevelle, tough luck I’m afraid.
Once you have all 6 chests, head to Baaj Temple and activate each glyph. You will now be able to access the Fayth.
Their Fayth is located in Remiem Temple. This temple is hidden in the Calm Lands and can only be accessed by chocobo. If you haven’t yet accessed chocobos, speak to the lady in the very north-west of the Calm Lands to train one. Once on a chocobo, head to the exit that leads to Bevelle, but continue east past the exit itself. Jump over to the opposite ledge and follow the path to find Remiem Temple.
Inside the temple, you will find Belgemine, another summoner that you may have already come across. The Chamber of the Fayth is just behind her, but it is blocked.
To open it, you have to find two key items.
One of said items is the Blossom Crown. To obtain this, you need to capture one of each monster in Mt Gagazet. The man at the Monster Arena will reward you for doing so with the Blossom Crown. For help on capturing monsters, see my Monster Arena Guide.
The second item you need is the Flower Sceptre. To get this, head back to Belgemine in Remiem Temple. Once you defeat her Bahamut in battle, she will give you the Flower Sceptre. You will have to defeat her other Aeons before you can fight Bahamut however.
I would recommend using an Aeon that can heal itself in battle. If you haven’t taught your Aeons curing abilities, simply have Ifirit use Fire on himself to heal, Shiva use Blizzara, etc.
Once you have completed all of the above, you will be able to access the Chamber of the Fayth and obtain the Magus Sisters. The three sisters appear in battle as a trio, which makes them all the more formidable then other Aeons. However, you do not have precise control over their attacks.
That concludes my hidden Aeon guide. Enjoy!