As everyone knows, WAR/NIN is a very popular job combination for a few reasons. It's usually because of Dual Weild and Utsusemi, which help maximize damage dealt while minimizing damage taken, and gives a lot of flexbility. Well, after some experimentation I've found a new use for /NIN: The Ninjutsu debuffs. No, I don't mean Hojo and Kurayami. I'm talking about Doton, Suiton, Raiton, Huton, Hyoton, and Katon. What's so great about them? They just do little to no damage and take four seconds to cast, right? Well, as you probably already know they lower the enemy's elemental resistances. What you probably didn't know is that they give -30 resistance for 15 seconds, and more importantly, the effect is guaranteed.
That's right, the effect cannot be resisted, no matter your level, the mob's level, your INT, the mob's INT, your Ninjutsu skill, or even if the enemy has a Barspell on against the ninjutsu's element. But how much is 30 resistance? To put it in perspective, a Threnody gives -50 resistance, -55 if the BRD uses a Threnody +1 instrument. Ancient Magic also gives -30 for 15 seconds. Also, through more testing I've discovered that every character has hidden resistance stats, and that those resistance stats are equal in value to the cap of a C-ranked skill. -30 resistance is downright crippling.
Now that brings us to the next point. Why do it? Why waste four seconds on an effect that's only going to last fifteen? Simple: Skillchains and Magic Bursts. At first glance, Skillchains do random and inconsistent damage. That's not true; skillchains are as consistent as spells are - they have a fixed damage. Even a "1st tier" (each consecutive skillchain is stronger than the last, I call these tiers for ease of reference) Level 1 skillchains will do 50% of the closing WS's damage - and that's nothing to scoff at, especially considering the damage a WAR can do.
The problem is, Skillchains, like all forms of magic, are prone to being resisted, which cuts down its effectiveness sharply. Resists on skillchains can be observed even on EP/DC mobs on elements they're neutral to, which says a lot for the probabilities of an IT resisting. Moreover, the more damaging your WS is, and the higher the tier and level of the skillchain you're closing, the more damage is at stake. That aside, lowering the mob's resistance also helps ensure a full Magic Burst (it's not a common thing, but resists still do happen on MBs! Nothing's uglier than seeing the BLM's MP being wasted, and having the mob still standing when you needed it to be dead to keep the chain going.) Those 4 seconds of casting the Ninjutsu can literally ensure hundreds of points in damage. That's far more than trying to get the most out of your WS's stat modifiers will do.
Of course, I'm sure Level 2 and 3 skillchains cause some confusion, since they have 2 and 4 elements respectively. I've tested this out, as well. A Level 60 BLM couldn't land Stun (not even with Elemental Seal) or Shock on a Too Weak Thunder Elemental no matter how hard he tried, and his Thunders didn't break 10 damage. On the other hand, when he closed Fragmentation (Wind/Lightning) the damage went completely unresisted. Likewise, his Aeros would always do full damage. I've done the same thing on Light Elementals - Flash won't stick, but Fusion does full damage, and I've done full damage Distortions on Thunder Elementals as well. It seems safe to me to assume that multielemental skillchains deal damage as a whole, and the resist rate is set by the element the enemy has least resistance to. Therefore, this trick still applies to Level 2 and Level 3 skillchains.
