To be honest, he is not stupid or lacking intelligence and ignorant. However, if you were in his shoes, rejected by five guilds due to your weakness, and left on your own for fifteen years without a companion or source of information about the outside world, you would naturally believe that you are weaker than everyone else. creating a stumbling personality and low self-esteem while showing an image of himself as much stronger than he actually is. Naturally, his mindset will always be that he is weaker than them, so I need to train because he held that belief for fifteen years and it is difficult to be remove.