If you’re planning to go into Fire Emblem Fate (or If in Japan) blind, don’t be afraid to check out the teaser. It offers more questions than answers so there’s no fear of any spoilers!
That said, the video shows a character named Aqua jumping off a bridge and the assumed protagonist plummets into the depth to save her. The teaser also titles the third scenario as the “Invisible Kingdom” as opposed to the first two’s “White Kingdom” and “Black Kingdom”.
The DLC for the Invisible Kingdom just got released in Japan at the cost of 2000 yen; roughly $16.50 USD. Intelligent Systems has promised that each scenario has as much content as Fire Emblem Awakening; so we’re looking at a game with a lot of value in it especially if you pay the discounted price for the 2nd scenario after the path you’ve chosen.
Fire Emblem Fates will be released to the west some time in early 2016 with no fixed date yet. This needs to remedied.