Dual Attack

So what am I increasing with Dual Attack Chance?

The chance of the unit I built (we’ll say Sez) attacking triggering a friendly unit (we’ll say Kise) to also attack, or a friendly unit(Kise) I have attacking triggering the unit I built(Sez) to attack?

The chance listed for any given character is going to be the probability that they assist the other character whose turn it is. For example, if you put Rosa Hargana on a Ranger like Schuri, he’ll become 7-14%% more likely to assist or Dual Attack (which is great because a lot of Rangers have Focus or beneficial effects on their basic Skill)

Annoying part is that this isn’t factored into the Dual Attack Chance stat listed on the left, even though the I believe the Unity Set bonus is.

So in general, the stat listed on the left is for that particular unit to attack which as you mentioned can be influenced by Unity Set bonus. Secondary question is if there is any way to affect this particular stat outside the Set Bonus?

The Rosa Hargana is a particular weird situation where it would have a secondary 7%-14% roll from my understanding of your description. Does this same awkward secondary also affect units like Taranor Guard and other similar circumstances where an artifact or ability has a dual attack trigger chance?

A little late, but besides the Unity set bonus, it can also be affected by:

Imprints for dual attack chance (stuff like Purrgis)
Taranor Guard has extra dual attack chance for himself only (as if he had Rosa, basically)
Rosa Hargana does NOT affect other Heroes - just the hero that it’s on.
Infinity Basket boosts everyone else’s Dual Attack chance during the owner’s turn.
CatRissa/Tamarinne guarantee a Dual Attack, chosen randomly afaik.