Demon Slayer: Kimetsu no Yaiba (2019)

S1E21 Against Corps Rules

Watching Tanjiro struggle to safeguard Nezuko, even as he falters, stirs up memories for Rui. Once a frail child, Rui transformed into a demon after encountering Muzan Kibutsuji, who infused him with his blood. However, following his transformation, his own parents turned against him, attempting to take his life. This traumatic experience has left him yearning for a family, an unachievable connection that continues to elude him.