Sculk Equipment

Upgrading to Sculk Equipment will require a piece of Diamond Equipment, an Infused Sculk Gem, and of course, a Sculk Upgrade smithing template. These templates can be found with a 10% chance in Ancient City chests. It might be wise to make a copy using a diamond and some Sculk before applying it...

Sculk Armor

Sculk Armor provides permanent Night Vision. No drawbacks. Neat, huh?

Sculk Sword

The Sculk Sword will turn simple mobs into "Thralls" which fight for you. There is a limit of 3 thralls at once, and 10-second cooldown between making thralls. Only "simple-minded" mobs such as undead and spiders can become thralls. Thralls are not persistent and can despawn, but they will follow you. Think of them more as a useful tool to distract enemies in a pinch than a faithful companion like a dog. Thralls will, however, remain yours between world loads (unless they despawn due to being on a server).

In addition to making Thralls, the Sculk Sword also allows collection of Soul Fragments and Phantom Soul Fragments.

Sculk Tools

Sculk Tools have a chance to drop 1XP when breaking non-ore blocks. It's not quite enough to sustain a tool with Mending, but good help either way.