The disclaimer:

I know that a lot of you already know this, and I know that I've been *ahem* persistent in sharing this information. However, I think that it's important to have a definitive record for posterity for anyone who looks for this information (since anything pertaining to Hybrids is a little cryptic at the moment, to be honest). Plus, this comes with proof, so nobody has to rely on hearsay and/or test it themselves later on down the road.

The actual stuff you came for:

Anyways, as the title states, Dual Wielding with Hybrid attacks takes on similar properties as both Physical and Magic attacks for their respective stats. The ATK portion of the calculations behaves like a standard Physical attack and excludes the opposite hand's ATK stat from the calculations. However, the MAG portion of the calculations behaves like a standard Spell and uses the cumulative MAG. This means that any time you're building a Hybrid unit with Dual Wield in mind, you are going to want to focus on the MAG stat as much as possible because it doesn't get split in the same way that ATK does - allowing you to reach a considerably higher potential output than an ATK build would allow.

The video evidence:

• MAG Test

• ATK Test

As you can see. The Phantasmal Blade manages to do roughly the same damage (if not more) on the second strike despite having no MAG stat itself. Conversely, The Sleep Sword does considerably less damage on the second hit than the Moonblade does. These results have been repeated multiple times ^{please don't send me back there anymore} so they're not flukes caused by the weapon's inherent damage variability (90%-110% for swords).

So yeah. Here's something a little more definitive when discussing the mechanics of how Hybrid attacks calculate their damage.

EDIT: /u/rusty815 did a pretty great breakdown of how this affects Fryevia's damage output in relation to the other Top-Tier damage dealers. Turns out that the only thing that can keep up with our Ice Queen is a fully-leveled Limit Burst from a BiS Olive. And now I have to eat crow for all the crap I've ever said about Hybrids...