Yesterday Nintendo released a new trailer officially adding 2 new characters from Fire Emblem to the Super Smash Bros character list, and officially confirming that fan favorite (and meme source) Captain Falcon would return. In addition to the trailer, the website now has 3 new banners with the faces of the characters linking to their individual pages.
The new Fire Emblem characters are both from Fire Emblem: Awakening. Robin, also known as the Avatar, is a character that is actually crafted and named by the player. Super Smash Bros uses the default (and likely canon) name of Robin in the game. Notably, in Fire Emblem: Awakening, players can choose the gender of Robin, male or female. The Super Smash Bros. trailer revealed near the end that the female version of Robin would be playable, likely as a different skin. Fans have speculated that this was a subtle jab at Ubisoft, who recently showcased an Assassin's Creed game with 4 male playable characters and no female.
The second playable character, oddly enough, is Lucina, a supporting character from Fire Emblem: Awakening. The choice seems odd because Fire Emblem: Awakening's true main character is Chrom, who is not a playable character in the new Super Smash Bros. While Chrom does appear during Robin's final smash as an assist, his absence as a playable character in favor of Lucina has some Fire Emblem fans scratching their heads. Likely reasons include the fact that the Smash Bros cast list from Fire Emblem include 2 current male characters, 1 former character who was male (Roy), and 1 character who appears to be male by default (Robin). Adding a female character like Lucina was probably for gender balance.
With the addition of these characters, the cast has reached 38 playable characters in total (Counting the 3 different playable Mii styles), which is larger than the cast list of Super Smash Bros Brawl which reached 35. This gap is likely to increase in size, since certain characters from previous games are still missing, including Ness and fan favorite Jigglypuff, both of which most fans speculate are likely to return.