Captain Falcon was an obvious character to appear the next Super Smash Bros as he was one of the original fighters, and his Falcon Punch is so iconic to the series. But Nintendo also added more characters from Fire Emblem.
The first is Robin who appeared in Fire Emblem: Awakening for 3DS who can use a thunder sword and magic. Since in Fire Emblem: Awakening, the character Robin can be either female or male (a choice given at the start of the game), both Robin incarnations will be in Smash Bros.
The other fighter Lucina is also from the 3DS Fire Emblem. She seems to use moves like Marth who is also in the game, but a bit different.