Both Ainz and King have a deep secret that they would never disclose to anyone. Ainz is actually bad at economics, politics, and other matters related to policy making. King, on the other hand, is actually incredibly weak. Fortunately for them, however, people always overestimate their abilities, be it as the ruler of a nation, or one of the top heroes in the country.

Jircniv Rune Farlord El-Nix, The Emperor of the Baharut Empire, considers Ainz one of the most intelligent and cunning leaders because he thought Ainz knew about his intention to form an alliance in order to beat the Overlord. The truth is actually not that exciting. Ainz simply happens to be at the same location as Jircniv when the meeting happens. He has no idea at all about Jircniv’s plan.

When Atomic Samurai, an S-Class Rank 4 Hero, challenged King to cut an apple with his katana, he was left speechless because he thought King managed to cut the apple at such incredibly high speed and precision to the point that the apple doesn’t even move at all after being cut. The truth is actually quite pathetic. Because King simply doesn’t have the strength to pull the sword out of the sheath, which means the apple hasn't even been cut yet.

Since everybody who knows them tends to overestimate Ainz and King’s abilities so much, they end up in a situation where they basically can do no wrong. You see, when people already have a preconceived notion of how smart or powerful you are, it doesn’t matter what you do, they’ll always think you’ve done something amazing. Even if in reality, you just messed up pretty badly.

One of Ainz’s biggest blunders is thinking that there shouldn’t be any spells or items in this new world that can hurt him or his servants, which was why he didn’t equip them with proper protective gear. As a result, Shalltear was brainwashed and Ainz was forced to kill her. However, his other servants ended up blaming Shalltear for her own carelessness instead. Not only that, but they also praise Ainz because he manages to force the enemy to reveal their strongest hands.

As for King, well, his career as Hero is filled with countless mistakes. One particular wrong thing that he often does is run away from a fight. Whenever he encounters a strong monster, he would use whatever means necessary to run away from that threat. Lucky for him, another hero (usually Saitama) always comes to defeat monsters and clean up his mess. That being said, he is known worldwide as the world's strongest man, so people always ended up giving him the credit for defeating the monsters that were actually beaten by someone else (usually Saitama).

As the saying goes, perception is reality. Once the people who know you perceive you in a certain way, it’s hard to change their preconceived notions about you. That is especially true for people who have a tremendous influence over other people, such as an S-Class Hero like King, or an overlord like Ainz.

As mentioned above, countless people highly overestimate Ainz and King’s strength and intelligence. That is why these two can never do anything wrong in the eyes of the masses. It’s not even an exaggeration to say that Ainz and King have become the subject of fear and admiration for a lot of people.

Ainz servants who live in Nazarick consider him as a Divine Being that stands above everything, while the rest of the world, especially Emperor Jircniv, consider him as the most powerful, cunning, and wisest being in the world. The King who can see 10,000 years into the future. Likewise, other than Genos, the rest of the S-Class heroes, and the general public as well, consider King as one of the strongest men in the world. Even Tatsumaki, the woman who can literally squeeze the earth, thinks extremely highly of King.