After saving Fuuka in Persona 3 Reload, you unlock a bunch of requests that require you to get a host of items, including something known as a Fashional Item.
While most items, such as Pine Resin and other similar side-quest items, are easy to obtain, the Fashionable Item is less so. You must complete certain tasks before you discover where to find it.
How to complete Request 29: ‘I want to look fashionable’ in Persona 3 Reload
Find Lustful Snake and get Black Quartz
To get the fashionable item Elizabeth is after, you must first delve into Tartarus in search of an enemy known as Lustful Snake, which drops the item Black Quartz when defeated.
Lustful Snakes are found from the 28th and 68th floor in Tartarus. They appear as a very strong enemy, distinguishablefrom normal shadows due to the strong red aura effects on their model. On the mini-map in the bottom left corner, a very strong enemy flashes red instead of being a static dot.
It is easier to find Lustful Snake the higher you are in Tartarus. So keep your eyes peeled and search the higher floors for a better shot at finding one. It’s completely random which strong enemy appears, though, so you might be looking for a while.
Take the Black Quartz to Club Escapade at Paulownia Mall
In the evening, any day after getting the Black Quartz, head to Club Escapade at Paulownia Mall. You need to be level two or higher in Courage stat to get inside.
In the corner of the club, there is an NPC with an exclamation mark above his head. Talk to him, and he will take the Black Quartz. You then have to buy glasses for 10,000 Yen, which gives you the item you need to take to Elizabeth.
When returning to Elizabeth to complete the request, you get five Power Incense I you can use to boost the Power stat of your character.