Izuku befriends with a Hedgehog to escape his bullying problems during childhood. Since he left, he gave the boy a rare emerald to help him become a Hero. Years later, a mad scientist and his empire launch a massive Invasion of Earth to create a One World Government. Now, Sonic, Izuku, and other heroes join forces to stop Eggman before its too late.
The story is, well, a crossover between Sonic the Hedgehog and My Hero Academia written by Toonami4Ever where Sonic gives Izuku one of the Chaos Emeralds to help the kid become a hero. Oh, and it's a harem story, too! The fic can be found here on Fan Fiction Dot Net.
This fanfic contains examples of:
- Adaptation Relationship Overhaul: In canon, Momo and Kendo didn't officially meet until their internship with Uwabami and neither have meet Camie. Here the three are childhood friends.
- Adaptational Badass: Thanks to the Chaos Emerald, Izuku is able to use One For All's full power with very little damage.
- Age Lift: A minor one, but in canon, Camie is a second-year student. Here she's a first-year.
- Anger Born of Worry: After the USJ, Momo is so mad at Izuku for nearly dying while fighting the Nomu she slaps him.
- Clueless Chick Magnet: Izuku has gained the affections of at least nine girls and seems unaware of their affection.
- Polyamory: As mentioned this is a harem story. Currently, the confirmed girls that will be interested in Izuku are Momo Yaoyorozu, Ochako Uraraka, Itsuka Kendo, Setsuna Tokage, Mina Ashido, Tsuyu Asui, Jirou Kyoka, Toru Hagakure, and Camie Utsushimi.
- The Tease: Momo begins to tease Izuku, both due to liking him and because she enjoys his reactions.
- Unwilling Roboticisation: Wouldn't be Eggman if he wasn't trying to do this to someone. He wants to subject All Might to this and succeeds with the Nomu at the USJ.