After the win at the World Pokemon Tournament Championships
Sonic marries Samus, while Tails Marries Elicina then Sonic amnd Samus have a son called Soul the Hedgehog, and Tails has a daughter called Crystal. After those events Sonic, Pikachu, and Dunsparce travel to a new reigon to start a new journey leaving Sonic's Pokemon behind to rest and relax.
