The Stacked Secret Ninja Art is the more generic variation, while the Secret Fusion Ninja Art are the special ones performed by two shinobi who are perfectly in sync.
To perform these tandem attacks, both characters must be in Shinobi form and have at least three Ninja Scrolls each. These are very powerful techniques, and damage all enemies in the current battle.
The power of these combined attacks goes up as the Affection between the two characters increases. Performing a Stacked Secret Ninja Art or Secret Fusion Ninja Art together is also a good way to help increase their affection levels quickly.
Each character (except Murasame) has two special Secret Fusion Ninja Arts, one that they do with a teammate and one that they do with their rival from the other faction. If two characters do not have a special Ninja Art together, then they do one of the generic Stacked Secret Ninja Arts instead.
If one of the characters is in "Chibi" form unlocked from the Waist-Deep DLC, then you cannot perform a Stacked Secret Ninja Art or Secret Fusion Ninja Art. Additionally, Murasame can only perform one with Ikaruga and nothing will trigger with anyone else.
Stacked Secret Ninja Arts
These are the generic attacks performed by various pairings, for when the characters do not have a special Secret Fusion Ninja Art to do together.
What the characters call out as they perform these attacks may change as the Affection between the two characters rises, but the attacks remain the same, only gaining power.
- The Best Combination (with Ikaruga)
- Deep Crimson (Ultimate Asuka + Crimson Homura)
Some of the names for these attacks are not official, and are based on comments made by the characters during the attacks.
- The characters can be seen utilizing some of these team-up attacks in the anime Senran Kagura: Shinovi Master -Tokyo Yōma-hen-.