On the subject of the successor to the Báb the Guardian states:

A successor or vicegerent the Báb never named, an interpreter of His teachings He refrained from appointing. So transparently clear were His references to the Promised One, so brief was to be the duration of His own Dispensation, that neither the one nor the other was deemed necessary. All He did was, according to the testimony of 'Abdu'l-Bahá in "A Traveller's Narrative," to nominate, on the advice of Bahá'u'lláh and of another disciple, Mírzá Ya˙yá, who would act solely as a figure-head pending the manifestation of the Promised One, thus enabling Bahá'u'lláh to promote, in relative security, the Cause so dear to His heart. [GPB28—29]

.He has also referred to him as "titular head" and "a mere figurehead". [GPB90]

"When the procession reached the public square, where the execution was to take place, Quddús, this youth of only twenty-seven years, cried out, "Would that my mother were with me, and could see with her own eyes the splendour of my nuptials!" As these words were being spoken the wild multitude fell upon him, tearing him limb from limb and throwing the scattered pieces into a fire which they had kindled for that purpose. Another account states that the Sa'ídu'l-'Ulamá had himself cut of Quddús' ears and struck him on the head with an axe." [TtP92]