There is a certain Playstation thief, who might also be a raccoon, that you can kind of cosplay as in Ghost of Tsushima. In order to dress up as this legendary thief, you will need to procure a couple of items. The first one is the Sly Tanuki Sword Kit in Kamiagata. The next item you need can be found at Jogaku Temple. Fast travel there and look for the tall building right outside of the main camp. At the top of this tall building will be the Crooked Kama Headband.
The next thing on this list will be the Gosaku’s Armor, which you get for completing The Unbreakable Gosaku. Once you have it, visit a normal Merchant and purchase the Ocean’s Guardian dye for it. The last item you need is a mask. Any mask will do in this situation, it seems, so there is no need to be picky. Once you have everything in place, simply equip all of it and the trophy will unlock.