Bitu (Bidu)

Bitu is attested in Mesopotamian literary and ritual texts as the named gatekeeper of the underworld. The Sumerian logogram writing of the name is dNE.TI (formerly read Neti), while the syllabic spellings include bi-tu, bí-ti, bí-du8 and related variants. Modern scholarship derives the name from the imperative form of Akkadian petû, 'open,' reflecting an origin and conceptualization tied to an Akkadian archetype of an underworld gate and fortified-city imagery. Textual attestation spans Sumerian and Akkadian sources across periods rather than a single mythic origin tale.

Most textual traditions emphasize Bitu's institutional role rather than a consistent bodily form. A late Assyrian visionary text (Underworld Vision of an Assyrian Prince) describes him as a hybrid creature with the head of a lion, feet of a bird and hands of a human; this physical description is attested only in that late visionary context and is not presented as a universally consistent iconography in the cited sources.

Bitu exercises custodial authority over the gates of the netherworld: he announces arrivals, instructs entrants (for example, telling Inanna to remove garments while passing the seven gates), and is named among lists of underworld functionaries and gatekeepers. In ritual and incantatory contexts, formulae place hostile beings (demons, ghosts) under the control of Bitu so they will return to or be confined within the underworld; thus his name functions operatively in exorcistic and household-protection texts. Textual traditions vary: in at least one text the doorkeeper role is instead assigned to Namtar, and Bitu's divine determinative is absent in some writings, indicating fluidity in assignment and status across sources.