Thief’s Wrap Mask
The first step is the easiest, you have to get the Thief’s Wrap.
It can be obtained from gift altars at any temple once enough offerings have been made to you. The mask is the second cosmetic obtained this way.
Gosaku's Armor
You need to complete Mythic Tale of The Unbreakable Gosaku. It begins at the start of Act 2, in the village of Akashima, by going to see Yamato the musician. You must then go and free the farmstead marked in red in Act 1 and 2 in order to recover the six keys held by the peasants.
The last step will take you to a stone door with a group of Mongols at the entrance, and you'll find the armor a bit of climbing afterward.
Ocean's Guardian Dye
You must have Gosaku's Armor for this step before purchasing the the Ocean's Guardian dye to the dye merchant from Act 2 for 10 flowers.
Crooked Kama Headband
You can find this item on top of Jokagu temple in Act 3. After taking the frozen lake temple with Yuna, climb the big pagoda. For this, position yourself just above one of the corners of the roof, jump then use the grapple with R2. Repeat until you reach the top, the headband is hung on an arrow.
Sly Tanuki sword kit
Finally, you need is the sword kit. Go to the Pillar of Honor East of Act 3 (see map below) to pick up the kit.
All you have to do now is combine all of this and enjoy your raccoon look.
Original content by Robin "Raiden" Bouquet.