Talk:Vagrant/@comment-4511886-20140630163303

The evil vagrants will spawn in another players world if you die with a lot of humanity. Good vagrants, and possibly also evil and phantom vagrants, spawn when you drop specific items (I believe the "specific items" are limited to the items that the specific vagrants drop.)

Source: Manual. This only stayed a mystery for so long because no one ever read it.

I'll write out the exact description if anybody is interested.

Vagrants
If you drop a certain item or lose a large amount of Humanity, those items and Humanity move to another player's world and form vagrant enemies.