Thread: Is this true?
I have not heard this name before, Arcormacolindóva, so I think it has likely been made up for the sake of role-playing. This doesn't mean that it is necessarily bad, just that it's not Tolkien canon. Sometimes the RPG have to 'gap-fill'.
Yes, it's a RPG thing again. The RPGers also made up names for all Nazgūl, while JRRT only gave one name : Khamūl.
It may have come from a piece of Fan Fiction somewhere.