Clothier

You do not find this vendor, you release him. He is the same character who paces outside the dungeon entrance warning you away from it, and killing the dungeon's guardian breaks the curse holding him there. The tattered clothes and the red eyes went with it. Once he is free all he needs is a vacant house, and he moves into town on his own.

That history is also his one mechanical use. Equip a Clothier Voodoo Doll, kill him after dark, and Skeletron spawns on top of you. It is the cleanest way to refight the boss, since you never walk back to the dungeon or sit through dialogue, and he returns the next morning like any other town NPC.

The doll has to be equipped for that to work. Killing him some other way, including by feeding him to something, is just a death with no boss attached.

His Red Hat exists only because he dies wearing it, which is the joke behind one of his lines. People build a shallow lava trench into his floor so he dies and respawns on a loop, leaving a hat each time. It works, and it is a trickle of copper. Doing the same murder at night with the doll on gives you a boss fight whose drops are worth vastly more for the same corpse. If you are going to kill him repeatedly, kill him properly.

He is not a bystander. When enemies come near he throws shadowflame skulls that hurt them and leave them burning, and his combat numbers climb quietly as you progress. Placing him at the edge of town where the spawns come in gives you a small permanent turret instead of one more thing to protect.

His shelf is the most heavily condition locked in the game, and almost none of it is on display at once. Time of day splits several outfits down the middle. Moon phase gates most of the hardmode wardrobe, one set per phase, so completing that list takes a full lunar cycle whatever else you are doing. Events add their own blocks: a blood moon, a party, Halloween, and the aftermath of specific fights, including a dead clown, a beaten Frost Legion and a defeated Lunatic Cultist, which itself splits again by day and night.

The one lever you control directly is the graveyard. Pile enough tombstones near his house and an entire funeral wardrobe appears in his stock, along with the Pretty Mirror, while the summer hat disappears for as long as the graveyard holds. A snow biome house unlocks a different single item. Moving him is the fastest way to see stock you would otherwise never load.

Three things on his shelf do real work. Black Thread and Pink Thread let you recolor dyes at a Dye Vat, which is the only route to shades the Dye Trader will never stock. The Familiar set covers your character in nothing at all, which is how you hide armor whose look you dislike. And once he is settled with a neighbor nearby he sells the pylon for whichever biome he lives in, so where you put him is a fast travel decision as much as a wardrobe one.

The Hunter Cloak is the outlier. It sits behind a golf score high enough that nobody reaches it by accident, so treat it as a reward for taking golf seriously rather than a purchase you can plan around.

He wants to live next to the Truffle, and the Truffle very much does not want to live next to him, for reasons their dialogue makes uncomfortably clear. Since content NPCs charge less, that pairing is a one sided discount: you get cheaper hats, the mushroom man gets worse prices and a worse night's sleep.

Most of his dialogue quotes films starring Tom Hanks, and one of the names he can be given nods to a long running Terraria YouTuber who uses him as an avatar. His muttering about tying a woman up and leaving her in the dungeon lines up with the Bound Mechanic you rescue down there, which he did while cursed and only half remembers, and it explains why he is so hostile to her afterward. Wearing his hat in front of him overrides every other line he has.