Code Vein 2 has a number of items that you’ll need to collect to upgrade your equipment, including your forma and jails. It gets confusing, since all items are representing by one of two colors of light blobs, so you can’t tell at a glance what you’ll be picking up.
Luckily, you can purchase an unlimited number of certain upgrade materials. Tender Light Stones of all four types can be purchased this way, but you have to find specific vendors to buy them from, then go to that same vendor when you buy them.
Buying Tender Light Stones
To buy unlimited Tender Light Stones, you need to visit four specific Jadwiga’s Minions. There’s one for each number of stone, and they’ll sell you Exclusive Customer Tokens. When you have the token from that minion, you’ll find that you can purchase the associated stones from that same minion.

So, if you visit the minion that sells Tender Light Stone 1, you’ll need to buy the Exclusive Customer Token: 01 from it. This then lets you continue buying as many Tender Light Stones 1s as you need. As you might expect, the pattern is the same for the other three vendors, where you need the token with the same number as the stones.
All Tender Light Stone Vendor Locations
For Tender Light Stone 1 and Tender Light Stone 2, you can find the vendors when you reach the Sunken City.

Jadwiga’s Minion for Tender Light Stone 1 is found on the far west side of the map.

The minion for Tender Light Stone 2 is found at the entrance of the Plagued Village, which you go through to reach Holly’s cocoon.

The Tender Light Stone 3 vendor is one you’ll come across by Bureau’s Castle, which you likely won’t reach until you’ve dealt with the first three heroes.

As for the Tender Light Stone 4 vendor, you won’t have access to them until Lady Lavinia tells you about a boat, which then lets you get to the little island that’s to the southwest of the mainland. On that island, Jadwiga’s Minion is in Insula Carcere Prison.
While you’ll find all types of Tender Light Stones scattered throughout the game to pick up, it’s much easier and more convenient to rely on the vendors that allow you to purchase unlimited amounts of these stones in Code Vein 2.

