Super Smash Bros. for Nintendo 3DS and Wii U

Super Smash Bros. for Nintendo 3DS and Super Smash Bros. for Wii U  (colloquially named Super Smash Bros. 4) are the upcoming fourth installments of the Super Smash Bros. series being developed for the Nintendo 3DS and Wii U. It is a sequel to Super Smash Bros. Brawl where Sonic made his debut. Like previous games in the series, they are being developed by Sora Ltd. along with Namco Bandai, and directed by Sora Ltd. founder Masahiro Sakurai. On June 2012, it was announced that Sora Ltd. is working alongside Namco Bandai Games in developing the games.

Development
In the Nintendo Direct of E3 2013, Mega Man from the Mega Man series by Capcom was announced as the guest character of the series (and the third 3rd-Party Character, after Sonic and Snake, to be in a Super Smash Bros. game). They also announced newer characters such as the Villager from the Animal Crossing series and the Wii Fit Trainer from Wii Fit. During a Q&A with Masahiro Sakurai, during the 2013 E3, it was revealed that both games may not come out at the same time. It was also revealed previous characters may not make it due to the Nintendo 3DS's space limitations.

On October 1st, 2013, during the Nintendo Direct presentation, Sonic the Hedgehog has been confirmed to be another playable character, making this his second appearance in the series since Super Smash Bros. Brawl. Windy Hill from Sonic Lost World is also recognized to be playable level in the game.

Trivia

 * Many fans speculate that Super Smash Bros. for 3DS and Wii U is the third and final video game for the Nintendo-Sega partnership along with Sonic Lost World and Mario & Sonic at the Sochi 2014 Olympic Winter Games. However, it was revealed by an interview with Aaron Webber that the third Sega-Nintendo Sonic the Hedgehog video game is something "completely different than before."
 * This is marks the first time that Sonic and Mega Man appear in a video game. Previously, both characters were featured in the crossover comic Sonic & Mega Man: Worlds Collide.