In order to unlock the World Champion, which is Wakka’s Celestial Weapon, you will need to play Blitzball. Specifically, you need to place third or better in a tournament. Once you do that, head to the Luca cafe, which is where you saw Biran and Yenke during your story visit here. When you have fulfilled the conditions, speak to the bartender, who will ask to see the Celestial Mirror. Use the Mirror and you will receive the World Champion.
Fully powered up, the stats for the World Champion are:
- Break Damage Limit
- Triple Overdrive
- Double AP
- Evade & Counter
The Jupiter Crest is found inside the Aurochs’ locker room in Luca. If you head to Luca and find the main lobby portion of the Blitzball stadium, their locker room will be on the right side up the stairs. Head down the hallway and actually into the locker room, where you’ll find the Jupiter Crest in the locked in the back.
The Jupiter Sigil will be a good grind, as you will need to be playing quite a bit of Blitzball. The Sigil will be available as a prize for a Blitzball League, but only after you’ve gotten all of Wakka’s Overdrives from the rewards. The catch for obtaining the Overdrives is to not actually start up the Tournament or League if the desired prize isn’t a part of it, since that will lock it in. Also, you will need to have participated in a total of 450 battles in order for the third Overdrive prize to be available.
One good tip in order to get the prizes to show up is to reset the game without exiting the Blitzball menu for the prizes, which should hopefully reset them. You can also keep exiting the Blitzball menu for Tournament prizes until it gets greyed out, then trying to get it available again to see if the prize you want becomes available. At the end of the day, the Jupiter Sigil will be available as a League prize, so you will need to play through two Tournaments and at least one League before you get it to show up (then the League for the Sigil itself).