First you need to kill Aspidochelone (HQ Adamantoise NM). Then you need to get Dryadic Abjuration: Feet to drop. Once that happens, you'll need some cursed sune-ate crafted (woot for divine lumber!). Once that's done, walk to the cathedral in northern sandy and talk/trade one of the npcs (he's in the room to the left and in the far corner). He'll talk some mumbo-jumbo and you get these boots.
In all honesty, forget these and go for Shura Haidate.