Hello and greetings to the people of the LOTR minecraft mod! Now that we have the pleasantries out of the way, on to the most serious business at hand...
Wraiths as a hire able unit. We must have them. And this is how it will happen.
Evil players will be getting a nerfed morgul blade, which shall only have one point of durability. When the morgul blade is used to strike a foe, it must break immediately, giving the player a morgul hilt afterwards. (Maybe.) This will make it more challenging, but the rewards will be great.
When one player stabs another, the player will receive the wither effect as normal. But if the poor soul who was stabbed withers away...
He will become a wraith like them.
Simply put, a wraith npc like a barrow wight will spawn with the deceased's username, and will fall under the command of the player who dealt the morgul wound.
I understand that there is an element of potential morgul-spamming that can go on here, but I am sure the mod authors have sufficient genius to configure it out. ?