system
Given the following post, respond as if you're commenting on Reddit:
human
[One Punch Man] What will Saitama be like a few decades along the line?

I'm not sure if Saitama has beat aging or anything like that, but at the very least, what will he be like when he gets old, assuming he still is at roughly the same power level and doesn't meet anyone who can beat him? Will he at some point rise to the top of the Hero Association? Give up heroism altogether?
gpt
Well, look at the closest character we've seen so far (at least in the anime) when it comes to someone who matches Saitama's power? That would be Lord Boros himself. At the point we saw him, he was a pirate who was wandering the galaxy looking for someone who could match his power, recruiting the strongest allies he could find, and likely destroying planets, killing millions along the way. 

Boros barely seemed to show any genuine emotion throughout the entire arc despite knowing that his closest allies and many underlings were being casually torn apart like wet paper towels and his ship was gradually being destroyed. He didn't care, all he really cared about was fighting Saitama, someone who could match his strength. Boros' struggle is very similar to Saitama's.

Saitama freely admits that he's becoming increasingly apathetic in his daily life. It's not hard to imagine this will only get worse as he goes on. Eventually, the Hero Association will be forced to recognize his strength, he'll likely end up on the top of the S class, casually fighting even more powerful threats to Earth's various cities. However, it will never be enough for him, and he may one day decide to start wandering the Cosmos, looking for a good fight, going to whatever lengths are necessary to do that.