Ajin, Kimetsu no Yaiba Recommendations
• Naive main character, living in his own perfect world, trying to be a decent human being.
• Both MC's go through traumatic incidents that changes their life.
•They both train to become stronger, better, smarter etc.
• Nagai has the intelligence, while Tanjiro has a sensitive nose.
• Both anime have fight between humanity and demi-humans.
Urokodaki and Satou have the same voice actor. Tosaki and Gyuu too.