What started as a simple question on Reddit turned into a full guide, and I decided to take this opportunity to continually update a resource for Dual Sword users in Monster Hunter Ultimate.
--The Butterfly Slash--
Forward step double slash: X while dashing from sheathed, and X+A with weapons drawn are the basic ways to perform this attack. Mid combo, after the basic A attack, you can move into this attack by simply hitting X. This is also how you perform this attack in Demonization mode, A --> X. More on combo usage of this attack later.
--Basic X Attacks--
Basic X: Left side slash.
Second X: Right side Slash.
Third X: Left side double windmill slash. This attack is a little slower, and opens you up to attacks for a moment. It still chains into other attacks, however.
X after forward step slash: Left-handed upwards slash. This attack can be chained into the basic X attack.
X after a Forward+B (forward roll): Also performs the left-handed upwards slash.
--Basic A Attacks--
Basic A: Double right-handed slash. Hitting A at any time during the X combo also
performs this attack
Second A: Full body spin slash. You kind spin 360 degrees with your swords out. This attack ends your combo and leaves you open for a moment.
Note that the forward step slash (X after A) is only able to be performed after the first A; after performing the second A attack, the full body spin slash, you're stuck finishing your combo.
--Basic Dual Sword Combos--
X+A (Or unsheathed dashing X) --> X --> X --> X --> X --> A --> A: Step in, followed by full standing combo. The last X in this combo leaves you open for a minute, as does the last A. For this reason, I mainly use...
X+A --> X --> X --> X --> A --> X, or B (Dodge): A step in, followed by a shortened, more fluid, standing combo. The X at the end of this combo is the forward step attack again. Often I use this to cut the side of the enemy and step towards it's back end at the same time. This combo leaves less openings. Also noteworthy, the X at the end of this combo is the first move of the very same combo, meaning it can be repeated infinitely. The step forward makes this impossible to chain infinitely against small targets however.
Now then, on to Demonization mode.
--Basic Demonization Abilities--
A word on Demonization activation: R+(X+A) while sheathed draws your weapons and goes straight into Demonization. R while standing, or as an interrupt after ANY standing attack causes you to go into Demonization. This means you can perform as many attacks as you like while in regular mode, and then move to Demonization to continue the combo. Even the second A, which is normally a combo-ender.
Demonization step-dash: B. Simply, the dodge button. This permits an agile step, that moves about 2/3rds the length of a regular dodge roll, but doesn't leave you open to any attacks, permitting you to move right into a combo. Amazing mobility, used to dodge a swing and continue the assault.
Standing X: Left side double windmill slash. The same attack as the third X.
Second X: Right side slash into scissor slash. This attack is something like 4 hits, and takes a moment.
Standing A: Full body spin slash. Yes, also the same as the second A. Yes, it also takes a moment. Yes, you can also use it at any time after an X attack. Where it differs however...
Forward + X after full body spin slash: Forward step slash. Oddly enough, all other times, simply pressing X is enough. Here, you have to press a direction as well.
X after Forward Step Slash: Left-handed upwards slash. These two moves retain after entering demonization.
Standing X+A: The Demon's Dance. A long series of complicated swords swings while standing in a given position. I'm willing to wager, the best DPS per button press of your kit, as you create a huge opening to use it. Spam against stunned monsters. This attack can follow any other attack in your Demonization mode.
X after a Forward+B (dodge): Still performs the left-handed upwards slash. Only the dodge changes.
X --> X --> A --> X+A: The full basic combo, utilizing every new move in the demonization kit, and finishing with the Demon's Dance. Honestly, I don't use this much. Until I know the exact weapon damage percentages for attacks, I attack a standing target by spamming X+A.
X --> X --> A --> Forward+X --> X -->...: An infinite combo, utilizing the forward step at the end of the basic attacks to chain back into the first attack. The ellipsis (...) denotes returning to the beginning of the combo. Again, until I see numbers, this is perhaps unnecessary, and I just spam X+A so that I don't accidentally move out of position with the forward steps.
Almost everything. There's one more mode worth mentioning, although there isn't a lot to it. It adds one additional attack, and one utility action. Despite it only adding a few abilities, it is the factor that will determine a mediocre Dual Sword user versus a Dual Sword master.
This mode is active when you are not in Demonization mode, but you have a full Demonization bar from landing attacks in Demonization mode. This mode is important because it increases your Dual Swords damage output, as well as your speed slightly. Very very importantly, it permits the use of the step dodges that you gain when in Demonization mode. Note, that both the step dodge, and the new attack gained in Archdemon mode drain some of your Demonization bar.
X+A in the middle of, or after, any standing attack: Archdemon's Dance. This is simply the last ~half of the swings from the Demon's Dance. Performing this attack drains your Demonization bar a little, leading me to believe these attacks hit pretty hard.
--Other general Dual Sword knowledge--
Stamina and Dual Sword management: An unbelievably important part of maximizing Dual Sword capabilities and efficiency. When in Demonization, your Stamina drains rapidly, although your damage goes up. When in Archdemon, utilizing the new abilities takes small chunks out of the Demonization bar, and simply being in this mode drains it slowly, while increasing your damage. If you land hits in Demonization without losing your entire Archdemon bar, the Archdemon mode remains active, even if you don't land enough hits to refill the entire bar. This means it's more efficient to switch into and out of Demonization often, keeping the bar from hitting empty.
Planning your kill, and how it fits Dual Swords: Getting a full bar against an enraged monster can be difficult. For this reason, I'd highly suggest utilizing some form of control (paralysis, traps or the like) to allow a small amount of time to get your bar to full, then, when the monsters enraged, you only need to combo in a double Demonization hits to keep your bar from emptying. Planning control abilities like this, and coordinating them with your team will be important in the full version.
Dash Juice use: With the heavy reliance on Stamina, Dash Juice becomes an excellent way to stay in Demonization without draining yourself. Please, by all means, use it. Do not rely on it, however. You'll have problems managing your Stamina/Archdemon mode when your out of Dash Juice if you use it as a crutch. Instead, plan your Dash Juice use around your monster control; Use Dash Juice to keep your bar up during those difficult parts, like rough enrages.
Team Play and Your Role: Obviously not a major concern until the main release. As is with using any other weapon, you should understand your role in a hunting party, as well as what other players can provide you. As a dual sword user, your role is very similar to a Sword and Shield user; user your agility and fast attack speed to stay on top of a target, consistently dealing damage. You can sever tails, albeit with great difficulty, and you cannot stun targets. For this reason, you're best off sticking on the weakest part of the center of the body, leaving the tail to players with larger reaching weapons, and the head to players with blunt weaponry. That said, consider also what your teammates can provide to you. Make sure you're in position whenever you expect a control status to apply to a monster. Consider what buffs allies can provide. Hunting Horn users have a recital that gives you infinite stamina, ala Dash Juice.
Thanks to Vegna871 from Reddit for the info on the Hunting Horn recital.
When we start to see some numbers for the weapon coefficient on Dual Sword attacks, some of my advice, namely the combos, will change. Until then, I believe these combo's to be the most efficient. That said, if anyone knows anything I don't, please, comment and let me know! I'll add it and credit you, thanks.
I hope you find my information useful, and good luck on your hunts!
- Useful skills and recommended armor sets: As the game releases and I've time to play, I will add information on particularly important skills to Dual Sword users, as well as some recommended armor sets for players who simply wish to grab something effective and go.
- Noteworthy monster specific information: While I want to keep this guide specific to Dual Swords, some information on particularly troublesome monsters, or monsters with particularly effective Dual Sword strategies would be worth recording.