Several of the early siyar sha’bīya include a black-Arab hero amid their significant agonists. Often, these black heroes are born to “white” Arab parents. They are thereby inserted into a heroic genealogy, though with a significant social handicap and a miraculous, mysterious ontology. Historically, these “genetic accidents” (per Lyons’ description) have been regarded as recycled avatars of the ‘Antara archetype; a half-black hero was included in later siyar in order to adhere to the parameters of the genre and use the trope of the indomitable black soldier. Our study leaves aside the problems that such a reading raises in naturalizing the displacement of homogenously Arab characters from a central position in these narratives, in addition to perhaps prematurely characterizing the siyar as a fully developed genre. Rather, the focus of this paper is the ontological circumstances of the black heroes in these texts. The paper asserts that narratives of these heroes' conceptions and births perform a significant and complex literary function that scholarship has not yet addressed. Using the case study of ‘Abd al-Wahāb in Sīrat al-Amīra Dhāt al-Himma, we explore the historicity of the claim that black children could be born to white parents. In so doing, we incorporate analogous attestations from exegetical literature, medical-scientific works, and adab treatises such as Ibn Ḥāzm’s Tawq al-Ḥamāma and al-Jaḥiẓ’s al-‘Ibr wa-l-‘Itibār, as well as the etiologies of race presented in qiṣaṣ al-‘anbīya’ anthologies. Each theory indicated in this array of texts explaining how a black child may be born to white parents, from atavism to the mixing of the nuṭfa with contaminating fluids, is in some way tested during ‘Abd al-Wahāb’s paternity case as it is appears in the 1909 edition of Sīrat al-Amīra Dhāt al-Himma, featuring a provincial qādī, a professional physiognomist, and a fictionalized Imām Ja'far al-Ṣādiq. This portion of the sīra, therefore, offers a wealth of collected popular beliefs and distilled “high cultural” views that, via jurisprudential or religious conduits, percolated throughout society and entered the sīra’s imaginary landscape. Most prominently, much like the philosophical inquiries staged in the aforementioned adab texts, the characters in the sīra use these assorted textual and paratextual gleanings to engage tensions between a scientific, teleological understanding of nature and the supernatural, supersessional power of Divine will. Explicating the enigmatic phenomenon of blackness-from-whiteness in Sīrat Dhāt al-Himma cuts to the very core of this tension, illuminating various strategies for its resolution.