Another character, Hercules (literally the same Greek god from mythology), also shows up in those same issues, and I doubt that Marvel has plans for him.
These issues aren’t strictly about the Black Knight and he just happens to be on the Avengers during these particular missions.
We’ve got already got Thor filling the god quota and Wonder Woman has the market cornered on Greek mythology.
It is odd that the Black Knight of all characters would be featured twice on these reprints, but that could be chalked up to a coincidence.