7. Descendant of Eighteenth Sultan.
(1) The Sovereign shall be a descendant acknowledged to be legitimately and lawfully begotten of the body and flesh and blood of the Eighteenth* Sultan.
(2) The descendant who shall be eligible to become the Sovereign shall be a son, grandson, great grandson and so on of the male line first, one generation after another until the last and it shall not on any account be permitted and it shall be unlawful to choose and appoint as Sovereign any person other than a descendant of the Eighteenth Sultan so long as such descendant of that Sultan exists:
Provided that no person shall be eligible, if he is considered and determined, after full and complete enquiry by the Dewan Negara, to have any great and serious defect derogatory to the qualities of a Sovereign such as insanity, blindness, dumbness or to possess any base quality on account of which he would not be permitted by the Hukum Shara’ to become a Sovereign
[*] Paduka Seri Sultan Ahmaddin Shah Ibni Almarhum Sultan Muhammad Shah was the 18th Sultan of Perak who reigned from 1792 to 1806.
Source: Article 7, PART II –THE LAWS OF THE CONSTITUTION OF PERAK.