It's really hard to say. Saitama has shown that he can defeat any opponent with a single punch. But Kenshiro is also extremely powerful in his own right, with his martial arts skills. However, if we consider Saitama's ability to break any limit, he might be stronger in a direct confrontation.
Wen Zhong and Bi Gan had different views on the status of the two. Some documents believed that Wen Zhong had the highest status because he was King Zhou's teacher and had extremely high prestige and influence. He controlled the core combat power of the Shang Dynasty, and he had been fighting for many years. He had pacified the North Sea and held military power. Bi Gan was King Zhou's uncle. Although he had a certain status, he was not as important as Wen Zhong. However, there was no clear answer as to who had a higher status. Therefore, it was impossible to determine who had a higher status in Wen Zhong and Bi Gan.
I think Saitama is stronger. His power is seemingly limitless and he has never struggled in a fight. Goku, although powerful, has had many intense battles where he was pushed to his limits.
Saitama is a very powerful hero in the One Punch Man universe. He can defeat any opponent with just one punch. He has a simple appearance and a somewhat laid - back personality.
The Shadow Stealer and An Emotion Stronger than Fear were two different books, and there was no direct comparison between them. The Shadow Stealer was a story about growing up, kinship, friendship, and love. It told the story of a boy growing up in different emotions. An Emotion Stronger than Fear was a novel by Mark Levy. It was described as a healing book that could mend the inner defects. Since there was no clear comparison or relation in the information provided, it was impossible to conclude that The Shadow Stealer was stronger than An Emotion Stronger than Fear.
It depends on how the author of the fanfiction has developed the plot and the characters. They could have given Natsu some special power - up or a unique situation that makes him stronger than Gildarts. For example, the author might have introduced a new form for Natsu that gives him an edge in combat, or perhaps they've weakened Gildarts in some way for the sake of the story. However, in the original series, Gildarts is extremely powerful, so this is a significant departure in the fanfiction.
Sometimes King is paired with Saitama. King, known for his false reputation of being a super - strong gamer in the original story, could be in interesting interactions with Saitama in the fanfiction's gaming context. Maybe they compete in a gaming tournament within the fanfiction, and Saitama's effortless wins baffle King.