Sonic Dynasty, known in Japan as Sonikku Hejjihoggu Eiyuu/Yami Musou (ソニック ヘッジホッグ 英雄／闇 無双, lit. Sonic Hedgehog Hero/Dark Musou) is a hack-and-slash action video game for Wii U, Xbox One, Playstation 4, and Playstation Vita. Developed by Omega Force, it's a collabooration between Omega Force and SEGA combining the gameplay of Warriors series with the world of Sonic The Hedgehog series.
The game begins with Sonic and his friends breaking into Dr. Eggman's base to try to stop him from unleashing his newest weapon. However, they are too late. Eggman reveals the device to them as the Egg Warper, a machine that allows people to travel across time and space. Using this device, he shoots Sonic's friends (missing Tails luckily), sending them throughtout time and space. He then reveals his plan to travel throught time and space to collect villians to create the ultimate team to take over the world, as well as find the Chaos Emeralds that he plans to put in the Egg Warper's hard drive to make it an all powerful machine of destuction.
Sonic and Tails escape back to Tails lab, where they to create their own "warper" to save their friends and stop Eggman's plan! From here the story spilts in half following either the Hero path (Sonic saving his friends, and recruting others and trying to collect the emeralds before Eggman) and the Dark path (Eggman recruting villians and looking for the emeralds).
Eventually, in a Final story, Eggman and his team manage to collect the Chaos Emeralds which he throws in to the Egg Warper's hard drive. However, the emeralds give the machine a mind of it's own and betrays Eggman's team. The now alive machine shoots the teams back to the first stage, where the machine starts warping time around them. The 2 teams decide to unite and eventually make it to the center of time itself, where the teams defeat Egg Warper, fixing time and space in the progress. Using his machine, Tails takes everyone back to there respective homes in time and space. The game ends with Sonic and friends rushing off into the sunset (leaving Eggman behind in the process) to go look for the Chaos Emeralds again, which were scattered back in the present by the Egg Warper's defeat.