For a fan of both Super Smash Bros. and Attack on Titan, this is about as good as it gets. Hell, if you're a fan of just one of them, this video by AmazingArtistYellow still will make your morning.
With the exception of Dr. Mario and Zero Suit Samus, the gang's all here for the upcoming Super Smash Bros. on Wii U and 3DS -- yes, Villager, you too, Wii Fit Trainer, you all get dramatic introductions. It took six months of work for AmazingArtistYellow to finish this video, so that 15 second disclaimer at the beginning can be forgiven.
Super Smash Bros x Attack on Titan Opening 2 [deviantART, h/t T.J.]