Rui was a disturbed individual who desired the close bonds that a family has and expected family members to perform their own roles. To him, "family members" who do not perform their roles as he expects them to (namely to protect Rui unconditionally or follow his instructions) are worthless and as good as dead. Despite the fact he yearns for a "family", his vision of one is incredibly twisted and founded on nothing but fear of him, instilled through repeated abuse on his fellow kin, which he does with unrepentant sadism. Well aware of his power, he is incredibly authoritarian and cruel and has no qualms about mistreating others or punishing his "family" by stringing them up and leaving them to be burned by the sun when they go against his wishes. Because of his strength, he tends to act almighty and confident, although this arrogance, while hardly unfounded, does not blind him to potential threats to his life.
Demon Slayer: Kimetsu no Yaiba
Since ancient times, rumors have abounded of man-eating demons lurking in the woods. Because of this, the local townsfolk never venture outside at night. Legend has it that a demon slayer also roams the night, hunting down these bloodthirsty demons. For young Tanjirou, these rumors will soon to become his harsh reality... Ever since the death of his father, Tanjirou has taken it upon himself to support his family. Although their lives may be hardened by tragedy, they've found happiness. But that ephemeral warmth is shattered one day when Tanjirou finds his family slaughtered and the lone survivor, his sister Nezuko, turned into a demon. To his surprise, however, Nezuko still shows signs of human emotion and thought... Thus begins Tanjirou's quest to fight demons and turn his sister human again. (Source: VIZ Media)
