Aether
Aether is a special skill that can be used by Ike from the Fire Emblem series in Super Smash Bros. Brawl. It will be his Up special move, and it will work similar to Marth's Dolphin Slash and Roy's Blazer. It is slightly different, however. He first tosses his sword in the air, which will hit a player. After about a second, he jumps up to grap his sword, hitting anyone in the way. He then swipes down with his sword, in a similar fashion to Kirby's Final Cutter move. He is resistant to attacks as he performs this move; he will still take damage, but he wouldn't even flinch. The official site stated this will be common with Heavy characters.
However, in the game Fire Emblem: Path of Radiance, it does not instantly knockout someone but instead gives an opponent heavy damage and recovers health equal to half of that damage.