Basically, each of your units is marked with a number, and on the phone version, you'd type that number to trigger that unit's part of the Unison Attack. For the DS version, the keypad is gone, but the numbers are still there. Of course, it has a long way to go before it can out-odd Knights in the Nightmare, a game in which you, as a ghost, take control of your units by possessing them.
Yggdra Unison trailer: welcome back to Dept. Heaven
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Basically, each of your units is marked with a number, and on the phone version, you'd type that number to trigger that unit's part of the Unison Attack. For the DS version, the keypad is gone, but the numbers are still there. Of course, it has a long way to go before it can out-odd Knights in the Nightmare, a game in which you, as a ghost, take control of your units by possessing them.

