Final Fantasy X Easter eggs

The 3 hidden aeons.
1) Yojimbo - After you defeat Defender X, you will find out that there is another bridge, but don't cross that bridge because it will take you away from that temple so look at it's right and you will see a ramp place so go inside there and go inside the cave. When you arrived infront of the cavern, then you will see the warp area. Go to the cavern then Tidus will follow Yuna to the Summon Room, the spirit will qppear and ask you questions so you must choose the third choice, then he will ask you 300,000 gils and give him half (150,000 gils). He will say, do we have a deal so give him 50,000 gils more (200,000 gils). Then, what do you know? You can summon Yojimbo!!!

2) Anima - First, you need to get the airship and talk to Cid, the screen will appear, press search and find the place like about X - 11 - 16, Y - 57 - 63, go there and save and jump down and you will meet your old friend GEOGAENO!!! The big fish!!! But you need all the destruction spheres from all the temple to unlock this Dark Aeon, Anima.

3) Magus Sisters - First of all, you need every Aeons in the game including Anima and Yojimbo. Once you have that, you are ready to go on with the Sidequest. First, head to Mt. Gagazet and capture every fiends there, there is a total of eleven fiends, look in the Monster Arena Section for a list of the fiends you can capture. Next, return to the Monster Arena owner in Calm Lands and he will reward you with the Blossom Crown. Then, go to Remiem Temple in Calm Lands and fight Belgemine. Since you probably have defeated her Valefor already, defeat her Ifrit for now. Here's the list of the prizes you win by defeating her.

Aeon Defeated Prize
Valefor Aeon's Soul
Power Sphere (x30)
Ifrit X-Potion (X30)
Ixion Chocobo Feather (X10)
Shiva Mega-Potion (X60)
Bahamut Flower Scepter
Yojimbo Shadow Gem (X8)
Anima Stamina Spring (X60)
Magus Sisters Shining Gem (X40)

Once you have defeated her Bahamut, you will have the Flower Scepter. Use both items on the north door and acquire the Magus Sisters. Now, return to speak to Belgemine and fight her own Magus Sisters to complete this Sidequest. After you have defeated her, you will get the Moon Sigil and you will also learn that Belgemine is an unsent. You can send her if you want, then this Sidequest is in the books!