Skullwaker on 08 October 2015
Here are a few videos Nintendo uploaded that are currently unlisted. They don't show too much that's new, but I thought they were worth sharing anyways! (they seem to be taken straight from the game without any extra audio)
The World of Genei Ibun Roku #FE
Mirage and Mirage Masters
Glamorous Entertainment Industry
Also, the Fire Emblem twitter account uploaded new toi8 art for Itsuki and Chrom:
