Definitely! The Hajime no Ippo manga has a compelling plot with lots of exciting boxing matches and emotional character arcs. The way it portrays the sport and the growth of the main character makes it really enjoyable.
One idea could be a crossover with 'Dragon Ball'. Ippo could train with Goku and learn some of his ki - based techniques. This would not only make Ippo stronger in the boxing ring but also introduce a new element to his fighting style.
I'm not entirely sure specifically what 'hajime horror story' is about as it could be a relatively unknown or very specific horror story. It might involve spooky elements like ghosts, monsters, or psychological scares.