Nightmare Mount

[Ravij]

The items that summon the GC leaders and the heroes of light are just that, single items which can summon 1 of three possible minions. See these:

Minion of Light: http://www.xiv-minions.com/single.ph...=minions&id=59
Wind-up Leader: http://www.xiv-minions.com/single.ph...=minions&id=60

As for the Behemoth Horn and Nightmare Whistle, they are two separate items.

Uh.. I'm a little confused; In the part you quoted I was stating that the Behemoth horn and Nightmare whistle are both two separate items. Someone thought the Nightmare whistle summoned the Behemoth mount and I corrected them.
I also realize that the new minions summon 1 of the three and they are not listed on the patch notes which if they are I must have skimmed over too quickly. I was clearing up someones confusion and now you've made me even more puzzled as to the reason of you quoting that particular post.