Complex sentence: He is a member of a clan of assassins and was raised to serve Kagura originally seen as a loyal servant but is actually a disturbed person whose desire is to kill Kagura and become a truly emotionless killer.
Split into simpler sentences: He is a member of a clan of assassins and was raised to serve Kagura. Originally seen as a loyal servant, he is actually a disturbed person whose desire is to kill Kagura and become a truly emotionless killer.