In Vampire Survivors update 0.6.1, a new Relic item, the Glass Vizard, was added. This unique item allowed you to unlock the ability to have a Vizard merchant in every single level in the game.
You’ll need to go through a few steps to unlock Glass Vizard. And ironically enough, you’ll have to talk to the first Vizard trader before you can unlock the others. Here’s how to unlock the Glass Vizard in Vampire Survivors.

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Where to find the Glass Vizard
The Glass Vizard relic is purchasable from theVizard merchantin theMoonglow stage. Once you’ve unlocked theMoonglowthe Vizard trader will be in the center of the stage.
The Glass Vizard costs 10000 gold and is only purchasable once. After you’ve unlocked it, the Vizard merchant will appear in all the levels. If you need more gold (as this is a quite expensive item), then grinding in the Moonglow stage is advisable. you may reliably farm around 4000-5000 gold in each run.

The Vizard trader has access to all weapons that are not conventionally accessible. So the Bone, Cherry Bomb, Carréllo, and Celestial Dusting. Each cost 1000 gold.
The other item at the Vizard merchant is the Golden Egg. This item permanently increases a random stat on the current character you’re using by a small amount. As a result, this item adds near-infinite scaling into the game.
For more guides and info on Vampire Survivors, check outHow to unlock the Moonglow stage in Vampire Survivorson Pro Game Guides.