Board Thread:Questions and Answers/@comment-61.6.238.10-20161107022633/@comment-27258569-20161216181556

Well to answer the OP's question, like others have said, Saitama doesn't kill humans.

Anyone in the series who's ever survived a fight with Saitama was because he wanted them to. As most know, he holds back in every single bout.

No one that we know of is even close to his level yet, though I think Blast or "God" might be possible candidates. However that's just speculation right now.