Well we want to keep K-Style in it, but the highest level weapon (Devil Arms) are completely new weapons with fully new animation. Example: Royal Guard gets a Shield, the animations are also different so you cannot K-Style with it (We can activate K-Style on that weapon tho... but we must think about it).
Also, i saw that video many times :p
At lvl 89 you choose one of the Legendary Weapons (Rebellion, Red Queen or Yamato) or at lvl 90 you choose the Devil Arm which is extremely cursed ( Alot of -HP and -AP) but it has alot of power.. also you cannot K-Style with it.