Complex sentence: Two years before the start of the series, Ao destroyed his village, killed his family, and carved out his heart, but Keno had refused to die, a fact that fascinated the demon princess Kokonoe.
Split into simpler sentences: Two years before the start of the series, Ao destroyed his village and killed his family. Ao also had carved out Keno's heart, but Keno had refused to die, a fact that fascinated the demon princess Kokonoe.