We kinda have two different types of Deus Ex Machina/plot armor characters fighting each other.
Heracles has the infinite endurance and power-up for every situation going on, which is dependent on a pain threshold (which of course is infinite for him as per plot) and has a usage limit which ends in death (also as infinite as it needs to be for the plot).
Jack has the infinite weaponry with ridiculous physics for him. Also his damage resistance is kinda weird, like I would've expected him to be glass cannon who'd go down from one direct hit by Heracles, but he took it better than expected. In this chapter he also showed an eye power.
I'm really interested how such differently written fighters who both get to have "Mary Sue"-esque abilities end up concluding this fight.
In other Mangas, such a fight would just seem ridiculous in a bad way, while here it's in a good way.