Headcanon 2

Bonded Tag Buddy, Assist Buddyfighter (Buddyfight)

I had thought If Buddyfight have tag.
Here is what I do.

When a Buddy bond reaches towards Gao and a Person(Or Michael, that's my OC) after their true power regains. The person have to ask Gao and Batzz to hold the card to Start a bond, forming a bond. And when Gao and Batzz hold it, They have to say "Raise the Flag, Together!" Then the card glow as it finally form a Bond. As of this, Tag Duels is available for any buddy.

This is called Assist Buddyfighter

The Assist Buddyfighter available to switch, and switch when the current buddyfighter lost it Life, The Assist Buddyfighter will take over the defeated Buddyfighter for action

Naturally, Assist Buddyfighter can also help the Buddyfighter to win by giving them Each one random cards. Monster, Impact or Even Magic.

Assist Buddyfighter however, cannot be change when the current buddyfighter is battling

But Assist Buddyfighter allowed to use magic items to heal the current Buddyfighter.