What is the ruling regarding a maternal uncle who commits adultery with his sister's daughter with her consent, leading to her pregnancy, and are they subject to a Hadd punishment, and what is their penalty?

Incest is one of the most heinous crimes and an indication of a perverted human nature. The child resulting from it is not attributed to the fornicator. Both individuals must repent, beware of seclusion and temptation, and maintain concealment. Scholars have differed regarding its punishment: the majority hold that it incurs the hadd punishment for zina (stoning for the married person and lashing for the unmarried), while Imam Ahmad, in one narration, held that the perpetrator should be killed unconditionally. The implementation of hudud (prescribed punishments) is the prerogative of the Imam (ruler), not individuals.