Thanks to the official Street Fighter X Tekken website, we now have firm details on exactly how Pandora Mode works.

Press ↓↓MP+MK simultaneously when your vitality gauge is under 25% to activate Pandora. When you activate Pandora, your partner’s strength will increase exponentially.

The power of the character who calls upon Pandora is necessary to fuel the technique. By sacrificing their vitality to Pandora, their partner will be able to enter Pandora mode.

Pandora is a system with a built-in time limit. In Pandora mode, the Cross Gauge will be filled to maximum capacity, and you will be able to use EX and Super Arts infinitely. However, if you are not able to defeat your opponent within the time limit, you will automatically be knocked out. Be careful when you use this technique!

The page also has details on scramble mode (in which you share your health with your partner), and an announcement about the Gem System. They note “My Ryu is different from your Ryu!? The traditional Cross Gauge from before now has slots above and below it! What exactly do these do!? You’ll find out more about this soon!” Wild.

[tip from Chindogg]