The series takes place in the Danganronpa universe.
All the Dakker assassins were originally the Ultimate Football Player, Ultimate Boomerang Thrower, Ultimate Carpenter, etc. Ken Hayakawa, meanwhile, is the original Ultimate Hope. Izuru Kamukura was an attempt to recreate him.Hayakawa Ken has a healing factor.
There are multiple times in the show where Ken is beaten literally black and blue, only to be completely fine and fresh faced five minutes later.