How to get Super Killer Moves

[Dio Brando]

Ive already cleared chapter 1 and 2, but I still dont have any super killer moves. There is still locked third training mission, because to unlock it I have to pick super killer move in slot, but I have none at my disposal. Am I doing something wrong or prehaps Ive got some kind bug? Or prehaps I need to continue main story and then some of the heroes will teach my new super killer moves?

[EOTWM]

Side quests. It's basically the same way you gain general killer moves, except you have to fully level up your social standing with other heroes (Complete all side quests that involve them).
After you complete side quests that involve certain heroes a red bar appears to show their relationship status with you, when that fills up completely you'll gain their super killer move. Not all heroes though, like Mumen Rider doesn't have one.