Are you trying to craft Demon's Gloves? Unless they've changed the drops, you can only get those fabrics from mobs that only spawn as part of the Mystery Potion quest... and it's not a likely drop. It's much easier to get those gloves from the HV Coin Quest. A pair of Demon's Gloves costs 200 Gold Wyverns.
I am trying to craft it all. Tunic gloves and stockings. This is not going to be a fun adventure if it doesnt drop well!! LOL
Ok, so I must buy the gloves for 200 g wyverns! What about the Tunic pattens and such??
None of the drop sites I use have the materials you need listed. They show that the recipes exist but not the mats. You can buy the Demon tunic and Demon Stockings from the Luxury Shop in Giran at fair prices (using C and D crystal). The Gloves (and I think the boots too) are available through the Coin Quest. I just don't think this set is meant to be crafted.
A certain unmentionable site lists the stockings as a full drop from Orfen, and the gloves as a full drop from Core. There is no entry for the Tunic, but I would nominate another dungeon boss, possibly the Ant Queen, Baium or Zaken.
demon top and bottom is best got from the lux shop. ahem, presteigous item hall I think it is now called on your map. or possible slightly cheaper from private shops around in giran.
boots and gloves, well. the mats for these are RARE. you can do the wishing potion quest for the glove fabric, not sure about the boots. I do know the coin quest pays off in demon gloves and possibly boots as well for level 2 members.
again, unless you are welling to wait a long time, best bought from private shops in giran. depending on your server, gloves and boots should be about a milion adena, each. maybe a little or more.