Two of Souma’s fiancées (later wives) are from long lived races - Aisha the dark elf, and Naden the Ryuu. That’s something that he needed to address - all else being equal he was going to die long before they even started looking older.

Dojyomaru is clearly a man* of culture given the number of #ARIAtheANIMATION shoutouts he* squeezes into #RealistHero but this scene here is almost a direct quote from one of the better episodes in #ARIAtheNATURAL