Artifacts are special items in the mod that require some hard effort to get, most likely a reference to something
As of right now, there is only one Artifact:

A VT7 High-Frequency sword of crimson color. One must sacrifice lots of effort and time to get one of these, but it is worth it

"There will be blood--shed!"

Stats:

10 DMG
0.3 Attack Speed
Unbreakable