Culture-hero / first-ancestor-of-death tier, rendered demigod given his world-shaping and life-after-death powers. Landtman's 1917 folk-tales and 1927 monograph are the standard primary sources. Name variants (Sido / Sído / Hido / Iko / Soido) occur across Fly-delta and Trans-Fly versions; English-leading 'First Man to Die', vernacular Sido in term. Vital status deceased: he is precisely the prototype of human death, though he persists as lord of Adiri.