Demigod (⅝ divine: a quartigod father, Peleus, and a fully-divine numen mother, Thetis — (¼ + 1)/2). The greatest of the Achaeans and the central figure of the Iliad; swift-footed, near-invulnerable save the heel, doomed to a short and glorious life. His wrath, withdrawal, and return to kill Hector frame the poem; he falls to Paris's heel-shot at the Scaean Gate. Formerly barred from the registry by the strict parentage rule (his mother being a Nereid) — now admissible, and computed a demigod by ordinary descent.