I thought I had heard that elemental weaknesses don't change damage done by jump abilities, and also that dual-wield doesn't hit twice in them, but I've been experimenting a bit with Shine's Hyper Dive and both seem to need more information.

I've been trying to boost my Nine to the point where he can one-shot the Elt boss. My current default set-up is dual-wielding the Holy Spear ( 82 atk, light) and Death Scythe ( 70 atk, non-elemental). In addition, I'm using a green beret, black belt gi, two Ruler Rings, two Atk 15%s (one from this event) and one Atk 10%, and I've put 15 power pots into him so far, bringing my total atk to 631.

The first thing I noticed is that when Nine lands, two numbers pop out. Also, those numbers aren't the same. So seems like dual wield does apply two hits, and it's relevant to note that my right hand atk should be 561 and my left hand atk is 549.

The second thing I did was experiment with different spears. In the above default setup, I'm doing a total of close to 500k damage, and he has 540k HP (my experiment involves paralyzing it with Black Cat Lid's Hex Strike, which works most of the time, and then guarding until Nine lands).

Then I switched the Holy spear to a Thunder spear, which sacrifices 34 atk, but changes to an element he has -50% resistance to from one he has no resistance or weakness to. This resulted in more damage, but not the 50% more damage that I'd have expected. It still wasn't killing him in one shot, it was just getting visibly closer.

Then I switched to using the Holy spear with the Thunder spear. This did less damage than with the Death Scythe/Thunder spear combo, but more than the original Holy spear/Death Scythe combo. Proportionally speaking, though, these damage differences were less than a 10% difference.

Finally, I sat down and tried to figure out what I expected the damage to be. In the default case, this is the best estimation I came up with for how much damage I was doing:

(hand1atk (561)² hand2atk (549)²⁾ / enemydef (40) * skill modifier (4.5) * level correction (2) * (1 jump damage bonus (250%)) = about 485k damage

(Note: the exvius wiki suggests the second jump damage bonus passive is 160% rather than 150%, which would also change the total slightly)

But of course, if all of that was then multiplied by (1 - elemental resistance (-50%)), even with a slightly lower atk, it should easily be way more than enough to one-shot that big robot. But here's something that's more consistent with my observations - what if the elemental resistance modifier was added to the jump damage bonus instead of multiplied in separately? Then the formula is like this:

(hand1atk² hand2atk²⁾ / enemydef * skill modifier * level correction * (1 jump damage bonus - elemental resistance)

Basically, instead of multiplying by 3.5 and then by 1.5, we multiply by 4. This comes out to about 521k damage in my lightning element combo and barely under 500k damage in my light/lightning element mix scenario, which sounds about right, at least eyeballing it. This also means that putting in an ice or fire spear (Who's been using Lad Mirazh, thinking it wouldn't make a difference?), I should cause a similar small difference in the opposite direction. That will probably be the next experiment.