One of the shops in Argent now has these insane things on sale. I bought the cheapest one and no, you can't just equip it.
I believe you have to use "apparel fusion" from the blacksmith in Shaitan to merge them into your gear, and it seems you also need fusion scrolls you get from Swamp/Forsaken City, and maybe more stuff too... Whatever this is, though, it sure sounds strong.