That is actually a question for a FFXIV question, not a question for this forum. I Googled it and since I don't play FFXIV I'm not sure about my answer.
It seems that you get it as part of the quest The Burdens We Bear. I will paste the 2 links below that I found. If this is wrong, sorry not sorry, I've not played at all ;-) Try Google if this doesn't work. Skyfiredancer (talk) 22:44, August 5, 2016 (UTC)