I just think that Nashid & Jakar went through castration (⊙…⊙ )

Can u tell me what is castration? What's its purpose and how it is affecting the plot? I might have missed something

Castration is when they cut off the testes of the male, effectively rendering them unable to impregnate others.

In this case them being castrated secures Shuraka's heirs as the only legitimate heirs, as there would be no other children with royal blood to threaten that status.